Absorbent Article with Bonded Web Material

ABSTRACT

An absorbent article to be worn the lower torso is provided. The absorbent article comprises a chassis comprising a topsheet, a backsheet, an absorbent core, and a pair of longitudinal barrier cuffs attached to the chassis. Each of the longitudinal barrier cuffs comprises a web of material. The web of material comprises a first nonwoven component layer, and a second nonwoven component layer. Each of the longitudinal barrier cuffs comprises a longitudinal zone of attachment where each of the longitudinal barrier cuff attaches to the chassis, a longitudinal free edge, and a plurality of mechanical bonds disposed between the longitudinal zone of attachment and the free edge. The plurality of mechanical bonds attach one of a first portion of the web of material to a second portion of the web of material, and the web of material to a portion of the absorbent article.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/303,187, filed Feb. 10, 2010, the substance of which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present disclosure generally relates to consumer products such asabsorbent articles and methods for manufacturing the same, and moreparticularly relates to mechanical bonds and mechanical bondingtechniques for absorbent articles comprising nonwoven webs and methodsof manufacturing the same.

BACKGROUND OF THE INVENTION

Nonwoven fabric webs may be useful in a wide variety of applications.Various nonwoven fabric webs may comprise spunbond, meltblown, spunbond(“SMS”) webs comprising outer layers of spunbond thermoplastics (e.g.,polyolefins) and an interior layer of meltblown thermoplastics. Such SMSnonwoven fabric webs may comprise spunbond layers which are durable andan internal meltblown layer which is porous but which may inhibit faststrikethrough of fluids, such as bodily fluids, for example, or thepenetration of bacteria through the fabric webs. In order for such anonwoven fabric web to perform to particular characteristics, it may bedesirable for the meltblown layer to have a fiber size and a porositythat assures breathability of the nonwoven fabric web while at the sametime inhibiting the strikethrough of fluids.

Absorbent articles such as diapers, training pants, incontinent wear andfeminine hygiene products, for example, may also utilize nonwoven fabricwebs for many purposes such as liners, transfer layers, absorbent media,barrier layers and cuffs, backings, and other components. For many suchapplications, the barrier properties of the nonwoven fabric web play animportant role in the performance of the fabric webs, such as theperformance as a barrier to fluid penetration, for example. Absorbentarticles may comprise multiple elements such as a liquid permeabletopsheet intended to be placed next to the wearer's skin, a liquidimpermeable backsheet which forms, in use, the outer surface of theabsorbent article, various barrier cuffs, and an absorbent core disposedbetween the topsheet and the backsheet.

When absorbent articles are produced, webs of materials, such asnonwoven materials, are bonded to each other. The bonding of thesematerials can be done for example via a mechanical bonding process.Reducing the manufacturing cost of absorbent articles by reducing thebasis weight of the webs while preserving, if not improving, theirfunctionality remains a challenge. For example, it is believed that whenthe combined basis weight of the webs to be bonded is less than 30 gsm,a reduction in basis weight of currently available spunbond, or SMSnonwoven webs can result in a significantly higher rate of bond defects.Those defects can lead to increased leakage of the absorbent article.There remains a need to provide an absorbent article comprising lowbasis weight webs that have a high quality of bonds with a low rate ofdefect when webs are bonded together.

There is also a need for low basis weight nonwoven webs that may be usedin the manufacture of absorbent articles at high production rates andpackaged under significant compaction for extended periods of time whileachieving and maintaining soft, air permeable (i.e. breathable) andliquid barrier materials with good tactile properties and good barrierproperties to low surface tension fluid. Structural, mechanical andfluid-handling properties of available nonwoven webs are believed not tobe sufficient. Therefore, there is also a need for improved nonwoven webstructures.

Absorbent articles that incorporate nonwoven webs in elements that actas barriers to liquids should be able to contain low surface tensionliquids. Currently available nonwoven webs often require expensivehydrophobic coatings or melt-additives that are added to the webs inorder to achieve satisfactory low surface tension fluid strike-throughtimes while remaining air permeable. It is believed that in addition totheir cost, such coated/treated nonwoven webs may still not besufficient to contain low surface tension body exudates with a surfacetension of 45 mN/m or less. As a result, there is a need for absorbentarticles comprising breathable elements made of lower cost nonwoven webshaving superior barrier properties. Such new nonwoven materials canenable the simplification of the absorbent article design, such as, forexample, replacing a multiple layer barrier cuff construction with asingle layer cuff construction.

SUMMARY OF THE INVENTION

In one embodiment, the present disclosure, in part, relates generally toabsorbent articles to be worn about the lower torso, which comprise achassis comprising a topsheet, a backsheet, and an absorbent coredisposed between the topsheet and the backsheet and a pair oflongitudinal barrier cuffs attached to the chassis. Each longitudinalbarrier cuff is formed of a web of material, the web of materialcomprises a first nonwoven component layer comprising fibers having anaverage diameter in the range of 8 microns to 30 microns and a secondnonwoven component layer comprising fibers having a number-averagediameter of less than 1 micron, a mass-average diameter of less than 1.5microns, and a ratio of the mass-average diameter to the number-averagediameter less than 2. The web of material has a local basis weightvariation less than 10%. Each of the longitudinal barrier cuffscomprises a longitudinal zone of attachment where the longitudinalbarrier cuff attaches to the chassis, a longitudinal free edge and aplurality of mechanical bonds disposed between the longitudinal zone ofattachment and the free edge. The plurality of mechanical bonds attachone of a first portion of the web of material to a second portion of theweb of material and the web of material to a portion of the absorbentarticle.

In one embodiment, the present disclosure, in part, relates generally toan absorbent article to be worn about the lower torso, which comprises achassis comprising a topsheet, a backsheet, and an absorbent coredisposed between the topsheet and the backsheet, and a pair oflongitudinal barrier cuffs attached to the chassis. Each longitudinalbarrier cuff is comprised of a first layer and a second layer, where thefirst layer and the second layer have a combined basis weight of lessthan 30 gsm. The first and second layers are each a web of material thatcomprises a first nonwoven component layer comprising fibers having anaverage diameter in the range of 8 microns to 30 microns and a secondnonwoven component layer comprising fibers having a number-averagediameter of less than 1 micron, a mass-average diameter of less than 1.5microns, and a ratio of the mass-average diameter to the number-averagediameter less than 2. The web of material has a local basis weightvariation less than 10%. At least one of the longitudinal barrier cuffscomprises a longitudinal zone of attachment where the longitudinalbarrier cuff attaches to the chassis, a longitudinal free edge and aplurality of mechanical bonds, where the plurality of mechanical bondsattach the first and second layers, and wherein the plurality ofmechanical bonds have a defect occurrence rate of less than 0.9%.

In one embodiment, the present disclosure, in part, relates generally toan absorbent article to be worn about the lower torso, which comprises achassis comprising a topsheet, a backsheet, and an absorbent coredisposed between the topsheet and the backsheet, a pair of longitudinalbarrier cuffs attached to the chassis. Each of the longitudinal barriercuffs is formed of a web of material. The web of material comprises afirst nonwoven component layer comprising fibers having an averagediameter in the range of 8 microns to 30 microns, and a second nonwovencomponent layer comprising fibers having a number-average diameter ofless than 1 micron, a mass-average diameter of less than 1.5 microns anda ratio of the mass-average diameter to the number-average diameter lessthan 2. The web of material has a local basis weight variation less than10%. At least one of the longitudinal barrier cuffs comprises a zone ofattachment where the barrier cuff attaches to the chassis, alongitudinal free edge and a plurality of mechanical bonds disposedbetween the zone of attachment and the free edge. The plurality ofmechanical bonds attach a first portion of the web material to a secondportion of the web of material and the web of material to a portion ofthe absorbent article to form a laminate, wherein the laminate of thefirst portion of the web of material and the second portion of the webof material has a total basis weight less than 25 gsm. Most of theplurality of mechanical bonds have a peel strength that is greater than50% of the tensile strength of the bonded material.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of the presentdisclosure, and the manner of attaining them, will become more apparentand the disclosure itself will be better understood by reference to thefollowing description of non-limiting embodiments of the disclosuretaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a plan view of an absorbent article in accordance with onenon-limiting embodiment of the present disclosure.

FIG. 2 is a perspective view of the absorbent article of FIG. 1.

FIGS. 3A-B are cross-sectional views of the absorbent article of FIG. 1taken along line 3-3.

FIG. 4 is a schematic diagram of a forming machine used to make anonwoven web of material in accordance with one non-limiting embodimentof the present disclosure.

FIG. 5 is a cross-sectional view of a nonwoven web of material in athree layer configuration in accordance with one non-limiting embodimentof the present disclosure.

FIG. 6 is a perspective view of the web of material of FIG. 5 withvarious portions of nonwoven component layers cut away to show thecomposition of each nonwoven component layer in accordance with onenon-limiting embodiment of the present disclosure.

FIG. 7 is a top view photograph of a web of material.

FIG. 8 is a cross-sectional photograph of the web of material of FIG. 7taken through a calendering bond.

FIG. 9 is a top view photograph of a web of material in accordance withone non-limiting embodiment of the present disclosure.

FIG. 10 is a cross-sectional photograph of the web of material of FIG. 9taken through a calendering bond in accordance with one non-limitingembodiment of the present disclosure.

FIG. 11 is a cross-sectional view of a web of material in a four layerconfiguration in accordance with one non-limiting embodiment of thepresent disclosure.

FIG. 12 is a perspective view of the web of material of FIG. 11 withvarious portions of nonwoven component layers cut away to show thecomposition of each nonwoven component layer in accordance with onenon-limiting embodiment of the present disclosure.

FIG. 13 is a top view photograph of a web of material in accordance withone non-limiting embodiment of the present disclosure.

FIG. 14 is a cross-sectional photograph of the web of material of FIG.13 in accordance with one non-limiting embodiment of the presentdisclosure.

FIG. 15 illustrates a simplified dynamic mechanical bonding apparatus inaccordance with one non-limiting embodiment of the present disclosure.

FIG. 16 illustrates a patterned cylinder in accordance with onenon-limiting embodiment of the present disclosure.

FIG. 17 is a plan view of a fragmentary portion of a bonded web ofmaterial in accordance with one non-limiting embodiment of the presentdisclosure.

FIGS. 18A-D illustrate patterns of bond sites in accordance with variousnon-limiting embodiments of the present disclosure.

FIG. 19 is a cross-sectional view taken along line 19-19 of FIG. 17,which illustratively shows a bond site in accordance with onenon-limiting embodiment of the present disclosure.

FIG. 20 is a cross-sectional perspective view of the bond site of FIG.19.

FIG. 21A illustrates mechanical bond quality and the templates fordetermining defects.

FIG. 21B illustrates the use of defect area templates for defects ofholes, skips and tears.

FIGS. 22-25 graphically illustrate data from Tables 1A and 1B of Example1.

FIG. 26 graphically illustrates the low surface tension fluidstrikethrough times of various samples of Table 2A of Example 2A.

FIG. 27 graphically illustrates the low surface tension fluidstrikethrough times of various samples of Table 2B of Example 2Bcompared the number-average diameter of the samples.

FIG. 28 graphically illustrates the sidedness of an SMNS web of thepresent disclosure having the properties specified in Table 2C.

FIGS. 29 and 30 graphically illustrate the low surface tension fluidstrikethrough times of various SMS webs compared with the low surfacetension fluid strikethrough times of the SMNS webs of the presentdisclosure.

FIG. 31 graphically illustrates the pore size distribution of Samples G,B, and A with respect to Example 3.

FIG. 32 graphical illustrates the bond defects of various samples ofTable 32 as a function of basis weight COV.

FIGS. 33A-33G illustrate examples of various mechanical bonds.

DETAILED DESCRIPTION OF THE INVENTION

Various non-limiting embodiments of the present disclosure will now bedescribed to provide an overall understanding of the principles of thestructure, function, manufacture, and use of the apparatuses and methodsdisclosed herein. One or more examples of these non-limiting embodimentsare illustrated in the accompanying drawings. Those of ordinary skill inthe art will understand that the apparatuses and methods specificallydescribed herein and illustrated in the accompanying drawings arenon-limiting example embodiments and that the scope of the variousnon-limiting embodiments of the present disclosure are defined solely bythe claims. The features illustrated or described in connection with onenon-limiting embodiment may be combined with the features of othernon-limiting embodiments. Such modifications and variations are intendedto be included within the scope of the present disclosure.

Definitions:

In this description, the following terms have the following meanings:

The term “absorbent article” refers to a device that is placed againstor in proximity to a body of a wearer to absorb and contain variousexudates discharged from the body. Example absorbent articles comprisediapers, training pants, pull-on pant-type diapers (i.e., a diaperhaving a pre-formed waist opening and leg openings, such as illustratedin U.S. Pat. No. 6,120,487, issued to Ashton, on Sep. 19, 2000),refastenable diapers, incontinence briefs and undergarments, diaperholders and liners, feminine hygiene garments, panty liners, andabsorbent inserts, for example.

The term “air permeability” is defined by the Air Permeability Test setforth below. Air permeability is set forth in m³/m²/minute (m/min).

The term “basis weight” is defined by the Basis Weight Test set forthbelow. Basis weight is set forth in grams/m² (gsm).

The term “bond area” refers to the area of an individual bond site. Bondarea is set forth in mm².

The term “bond density” is the number of bonds in an area. Bond densityis set forth in bonds per cm². A relative bond area is the bond densitymultiplied by the bond area (all converted to same unit area), and givenin a percentage.

The term “cross direction” refers to a direction that is generallyperpendicular to the machine direction.

The term “defect occurrence rate” is defined by the Defect OccurrenceRate Test set forth below.

The term “denier” refers to a unit of fineness of a fiber that is equalto the weight (in grams) per 9000 m of fiber.

The term “diameter” when referring to fibers is defined by the FiberDiameter and Denier Test set forth below. Diameter of fibers is setforth in microns.

The term “elongatable material,” “extensible material,” or “stretchablematerial” are used interchangeably and refer to a material that, uponapplication of a biasing force, can stretch to an elongated length of atleast 150% of its relaxed, original length (i.e. can stretch to 50% morethan its original length), without complete rupture or breakage asmeasured by EDANA method 20.2-89. In the event such an elongatablematerial recovers at least 40% of its elongation upon release of theapplied force, the elongatable material will be considered to be“elastic” or “elastomeric.” For example, an elastic material that has aninitial length of 100 mm can extend to 150 mm, and upon removal of theforce retracts to a length of at least 130 mm (i.e., exhibiting a 40%recovery). In the event the material recovers less-than 40% of itselongation upon release of the applied force, the elongatable materialwill be considered to be “substantially non-elastic” or “substantiallynon-elastomeric”. For example, a material that has an initial length of100 mm can extend at least to 150 mm, and upon removal of the forceretracts to a length of 145 mm (i.e., exhibiting a 10% recovery).

The term “elastic strand” or “elastic member” refers to a ribbon orstrand (i.e. great length compared to either width and height ordiameter of its cross-section) as may be part of the inner or outer cuffgathering component of an article.

The term “fiber” refers to any type of artificial fiber, filament, orfibril, whether continuous or discontinuous, produced through a spinningprocess, a meltblowing process, a melt fibrillation or film fibrillationprocess, or an electrospinning production process, or any other suitableprocess.

The term “film” refers to a polymeric material, having a skin-likestructure, and it does not comprise individually distinguishable fibers.Thus, “film” does not include a nonwoven material. For purposes herein,a skin-like material may be perforated, apertured, or micro-porous andstill be deemed a “film.”

The term “grommet ring”, or “grommet”, refers to a ring (not necessarilycircular or oval) that is formed around the periphery of a mechanicalbond site. FIG. 19 shows a bond site 351 b with a bottom surface 351 bband a grommet ring 376.

The term “hydrophobic” refers to a material or composition having acontact angle greater than or equal to 90° according to The AmericanChemical Society Publication “Contact Angle, Wettability, and Adhesion,”edited by Robert F. Gould and copyrighted in 1964. In certainembodiments, hydrophobic surfaces may exhibit contact angles greaterthan 120°, greater than 140°, or even greater than 150°. Hydrophobicliquid compositions are generally immiscible with water. The term“hydrophobic melt additive” refers to a hydrophobic composition that hasbeen included as an additive to a hot melt composition (.i.e., blendedinto a thermoplastic melt), which is then formed into fibers and/or asubstrate (e.g., by spunbonding, meltblowing, or extruding).

The term “hydrophobic surface coating” refers to a composition that hasbeen applied to a surface in order to render the surface hydrophobic ormore hydrophobic. “Hydrophobic surface coating composition” means acomposition that is to be applied to a surface in order to provide ahydrophobic surface coating.

The term “local basis weight variation” is defined by the Local BasisWeight Variation Test set forth below. Local basis weight variation isset forth in percentage.

The term “low surface tension fluid” refers to a fluid having a surfacetension of less than 45 mN/m.

The term “low surface tension fluid strikethrough time” is defined bythe Low Surface Tension Fluid Strikethrough Time Test set forth below.Low Surface Tension Fluid Strikethrough Time is set forth in seconds.

The term “machine direction” (MD) refers to the direction of materialflow through a process.

The term “mass-average diameter” refers to a mass-weighted arithmeticmean diameter of fibers calculated from the fiber diameter, which ismeasured by the Fiber Diameter and Denier Test set forth below.Mass-average diameter of fibers is calculated by the Fiber DiameterCalculations set forth below. The mass-average diameter of fibers is setforth in microns.

The term “mean-flow pore diameter” in a nonwoven sample refers to a porediameter corresponding to pressure at which the flow through pores in a“wet sample” is 50% of the flow through pores in a “dry sample”. Themean flow pore diameter is measured by the Pore Size Distribution Testset forth below. The mean-flow pore diameter is such that the 50% offlow is through pores larger than the mean-flow pore diameter, and therest of the flow is through the pores smaller than the mean-flow porediameter. The mean-flow pore diameter is set forth in microns.

The term “calender bond” or “thermal bond” refers to a bond formedbetween fibers of a nonwoven by pressure and temperature such that thepolymers within the bond melt together to form a continuous film-likematerial. The term “calendar bond” does not comprise a bond formed usingan adhesive nor through the use of pressure only as defined bymechanical bond below. The term “thermal bonding” or “calender bonding”refers to the process used to create the thermal bond.

The term “mechanical bond” refers to a bond formed between two materialsby pressure, ultrasonic attachment, and/or other mechanical bondingprocess without the intentional application of heat. The term mechanicalbond does not comprise a bond formed using an adhesive.

The term “mechanical bonding” refers to the process used to create amechanical bond. As used herein, the term “nonwoven” means a porous,fibrous material made from continuous (long) filaments (fibers) and/ordiscontinuous (short) filaments (fibers) by processes such as, forexample, spunbonding, meltblowing, carding, and the like. “Nonwoven”does not include a film, woven cloth, or knitted cloth.

The term “nonwoven component layer” refers to one sheet, ply or layer ofa web of material. The term “number-average diameter,” alternatively“average diameter”, refers to an arithmetic mean diameter of fiberscalculated from the fiber diameter, which is measured by the FiberDiameter and Denier Test set forth below. Number-average diameter offibers is calculated by the Fiber Diameter Calculations set forth below.The number-average diameter of fibers is set forth in microns.

The term “polydispersity” refers to a measure of the width of adistribution calculated by a ratio of the mass-average diameter to thenumber-average diameter.

The term “porosity” refers to a measure of void volume of the nonwovenlayer with the fibers composed of a material, and is calculated as(1−[basis weight]/[thickness×material density]) with the units adjustedso that they cancel out.

The term “relative standard deviation” (RSD) refers to a measure ofprecision calculated by dividing the statistic standard deviation for aseries of measurements by the statistic average measurement of theseries of measurements. This is often also called coefficient ofvariation or COV.

The terms “web” or “web of material” refer to a sheet-like structuresuch as a nonwoven or a film.

Nonwoven webs of material, such as nonwoven fabric webs, may comprisesheets of individual nonwoven component layers bonded together usingmechanical, thermal, or chemical bonding processes. Nonwoven webs may beformed as flat, porous sheets made directly from individual fibers, frommolten plastic, and/or plastic film. Some nonwoven structures may bestrengthened or reinforced by a backing sheet, for example. Nonwovenstructures may be engineered fabrics that may be a limited life,single-use fabric, or a very durable fabric. In various embodiments,nonwoven webs provide specific functions, such as absorbency, liquidrepellency, resilience, stretch, softness, strength. These propertiesare often combined to create fabrics suited for specific applications,while achieving a good balance between product useful life and cost.

Continuous and discontinuous fiber spinning technologies of moltenmaterials and typically of thermoplastics are commonly referred to asspunmelt technologies. Spunmelt technologies may comprise both themeltblowing process and spunbonding processes. A spunbonding processcomprises supplying a molten polymer, which is then extruded underpressure through a large number of orifices in a plate known as aspinneret or die. The resulting continuous fibers are quenched and drawnby any of a number of methods, such as slot draw systems, attenuatorguns, or Godet rolls, for example. In the spunlaying or spunbondingprocess, the continuous fibers are collected as a loose web upon amoving foraminous surface, such as a wire mesh conveyor belt, forexample. When more than one spinneret is used in line for forming amulti-layered web, the subsequent nonwoven component layers arecollected upon the uppermost surface of the previously formed nonwovencomponent layer.

The meltblowing process is related to the spunbonding process forforming a layer of a nonwoven material, wherein, a molten polymer isextruded under pressure through orifices in a spinneret or a die. Highvelocity gas impinges upon and attenuates the fibers as they exit thedie. The energy of this step is such that the formed fibers are greatlyreduced in diameter and are fractured so that micro-fibers ofindeterminate length are produced. This differs from the spunbondingprocess where the continuity of the fibers are generally preserved.Often meltblown nonwoven structures are added to spunbond nonwovenstructures to form spunbond, meltblown (“SM”) webs or spunbond,meltblown, spunbond (“SMS”) webs, which are strong webs with somebarrier properties.

Other methods to produce fine fibers comprise melt fibrillation andelectrospinning. Melt fibrillation is a general class of making fibersdefined in that one or more polymers are molten and are extruded intomany possible configurations (e.g., co-extrusion, homogeneous orbicomponent films or filaments) and then fibrillated or fiberized intofilaments. Meltblowing is one such specific method (as describedherein). Melt film fibrillation is another method that may be used toproduce submicron fibers. A melt film is produced from the melt and thena fluid is used to form fibers from the melt film. Examples of thismethod comprise U.S. Pat. Nos. 6,315,806, 5,183,670, and 4,536,361, toTorobin et al., and U.S. Pat. Nos. 6,382,526, 6,520,425, and 6,695,992,to Reneker et al. and assigned to the University of Akron. The processaccording to Torobin uses one or an array of co-annular nozzles to forma tube of film which is fibrillated by high velocity air flowing insidethis annular film. Other melt film fibrillation methods and systems aredescribed in the U.S. Pat. Publ. No. 2008/0093778, to Johnson, et al.,published on Apr. 24, 2008, U.S. Pat. No. 7,628,941, to Krause et al.,and U.S. Pat. Publ. No. 2009/0295020, to Krause, et al., published onDec. 3, 2009 and provide uniform and narrow fiber distribution, reducedor minimal fiber defects such as unfiberized polymer melt (generallycalled “shots”), fly, and dust, for example. These methods and systemsfurther provide uniform nonwoven webs for absorbent hygiene articles.

Electrospinning is a commonly used method of producing sub-micronfibers. In this method, typically, a polymer is dissolved in a solventand placed in a chamber sealed at one end with a small opening in anecked down portion at the other end. A high voltage potential is thenapplied between the polymer solution and a collector near the open endof the chamber. The production rates of this process are very slow andfibers are typically produced in small quantities. Another spinningtechnique for producing sub-micron fibers is solution or flash spinningwhich utilizes a solvent.

There is a distinct difference between submicron diameter fibers madewith electro-spinning versus those made with melt-fibrillation, namelythe chemical composition. Electro-spun submicron fibers are made ofgenerally soluble polymers of lower molecular weight than the fibersmade by melt-fibrillation. Commercially-viable electro-spinning methodshave been described in U.S. Pat. No. 7,585,437, to Jirsak et at, U.S.Pat. No. 6,713,011 to Chu et al., and U.S. Pat. Publ. No. 2009/0148547,to Petras et al. Electro-spinning is recently explored in combinationwith a molten polymer rather than a polymer solution, as described in areference by Lyons et al., “Melt-electrospinning Part I: ProcessingParameters and Geometric Properties”, published in the journal POLYMER45 (2004) pp. 7597-7603; and by Zhou et al., “The Thermal Effects onElectrospinning of Polylactic Acid Melts”, published in the journalPOLYMER 47 (2006) pp. 7497-7505. The researchers in these studies haveobserved that electrospun fibers have average diameters generallygreater than 1 micron as compared to solution electrospun fibers thatare submicron (i.e., less than 1 micron). With motivation to reduce thefiber diameter, researchers have more recently started optimizingprocess and polymer parameters. Generally, the goal of the researchershas been to reduce the number-average diameter, but not reduce themass-average diameter, and narrow the fiber diameter distribution.Improvements in melt electrospinning show that fiber diameter may bedecreased, though to a limited extent but still above 1 micron(generally, in the range of 2 micron to 40 micron for polypropylene withmolecular weights in the range of 12,000 to 200,000 Daltons) by theresearch works of Kong et al., “Effects of the Spin Line temperatureProfile and Melt Index of Poly(propylene) on Melt-electrospinning”,published in the journal POLYMER ENGINEERING AND SCIENCE 49 (2009) pp.391-396 (average fiber diameter of 20 micron using polypropylene of meltflow index of 1500); by Kadomae et al., “Relation Between Tacticity andFiber Diameter in Melt-electrospinning of Polypropylene”; published inthe journal FIBERS AND POLYMERS 10 (2009) pp. 275-279 (fiber diametersin the range of 5-20 microns using polypropylene with 12,000 and 205,000molecular weight), and by Yang et al., “Exploration ofMelt-electrospinning Based on the Novel Device”, published in theProceedings of the IEEE International Conference on Properties andApplications of Dielectric Materials, 2009, pp. 1223-1226 (finest fiberdiameter of 5 micron). Most recently, the melt electrospinning has beenmodeled by Zhmayev et al., “Modeling of Melt Electrospinning forSemi-crystalline Polymers”, published in the journal POLYMER 51 (2010)pp. 274-290. Even their models show that the fiber diameter of meltelectrospun Nylon 6 (with a melt flow index of 3) is 2 microns, similarto that obtained by experiments. A prior work by Dalton et al.,“Electrospinning of Polymer Melts: Phenomenological Observations”,showed that fiber diameter of melt electrospun high molecular weightpolypropylene fibers (with MFT in the range of 15 cm³/10 min to 44cm³/10 min) may be significantly reduced to submicron by adding 1.5% ofviscosity reducing additive, such as Irgatec CR 76 (from Ciba SpecialtyChemicals, Switzerland). However, viscosity reducing additives, such asIrgatec CR 76, for example, significantly reduce the molecular weight ofthe polymer, as described in U.S. Pat. No. 6,949,594 to Roth et al., andby Gande et al., “Peroxide-free Vis-breaking Additive for ImprovedQualities in Meltblown Fabrics”, in the conference proceedings of theInternational Nonwovens Technical Conference, 2005, St. Louis, Mo., USA.Therefore, melt electrospun fibers have fiber diameters generally above1 micron, or a high standard deviation leading to a broad fiber diameterdistribution using commercial-grade high molecular weight polymers.Also, the polymer used in successful electrospinning of polymer meltsuses a polymer of low molecular weight, e.g., in the case of PLAstarting from 186,000 Dalton and degrading to actually 40,000 Dalton inthe spun fibers used by Zhou et al., and use of viscosity reducingadditive Irgatec CR 76 by Dalton et al. to reduce the melt viscosity byreducing the molecular weight. This compares to PLA used inmelt-fibrillation processes of where e.g. the Natureworks 6202D resinstarts at a molecular weight Mw of 140,000 Dalton and ‘degrades’ only toa molecular weight of 130,000 to 135,000 Dalton compared to the 40,000of the melt-electrospun fibers. Also other grades of PLA (e.g. with Mwof 95,000 or 128,000) drop in molecular weight from neat resin to fiberform by less 10,000 or even less than 1,000 Dalton (less than 10% orless than 1%). Therefore, not only is the electrospinning processincluding the melt-electrospinning process at present still low inthroughput, but it is structurally and chemically distinct from the finefibers (i.e., the second nonwoven component layer) of the presentdisclosure. However, it is desirable to develop the electrospinningmethod towards making fine fibers at higher throughput and a narrowsubmicron diameter distribution as described herein.

In various embodiments, the fibers of the nonwoven structure may be madeof polyesters, including PET and PBT, polylactic acid (PLA), and alkyds,polyolefins, including polypropylene (PP), polyethylene (PE), andpolybutylene (PB), olefinic copolymers from ethylene and propylene,elastomeric polymers including thermoplastic polyurethanes (TPU) andstyrenic block-copolymers (linear and radial di- and tri-blockcopolymers such as various types of Kraton), polystyrenes, polyamides,PHA (polyhydroxyalkanoates) and e.g. PHB (polyhydroxubutyrate), andstarch-based compositions including thermoplastic starch, for example.The above polymers may be used as homopolymers, copolymers, e.g.,copolymers of ethylene and propyelene, blends, and alloys thereof.

A variety of mass-produced consumer products such as diapers, papertowels, feminine care products, incontinence products and similarmaterials, employ nonwoven webs, such as SMS webs, in their manufacture.One of the largest users of SM and SMS webs is the disposable diaper andfeminine care products industry. When the nonwoven webs are incorporatedin an absorbent article, however, achieving a barrier against fluidsthat have a surface tension on a similar level of the surface energy ofthe SMS structure is sometimes difficult. For example, some SMS webs mayhave a surface energy level of approximately 30 mN/m, e.g., when made ofPP, while the fluids sought to be blocked (i.e., infant urine or runnyfeces) may have surface tensions of 40-50 mN/m, or in some cases as lowas 32 to 35 mN/m. For various components of absorbent articles, such asbarrier leg cuffs, for example, in order to achieve a desired fluidbarrier, hydrophobic surface coatings may be applied to the webs orhydrophobic melt-additives may be used in the production of the nonwovenwebs. Such techniques, however, may add to the production costsassociated with the absorbent product and generally increase theproduction complexity. If hydrophilic surfactants or materials are usedon other portions of the absorbent article (such as for example thetopsheet), they may migrate or wash off toward other absorbent articlecomponents during wet and/or dry conditions. During dry conditions, forexample, the hydrophilic surfactants or materials may migrate afterabsorbent articles are manufactured and packaged and while being storedover the course of weeks and attach to the barrier cuff, thereby,possibly leading to an increased leakage rate. In addition, during wetconditions, the hydrophilic surfactants or materials may also wash offof a diaper topsheet, for example, and then attach to the barrier cuffs,thereby, again possibly leading to an increased leakage rate. Oneadvantage of the additional hydrophobic materials in the web is thatthey resist and repel the hydrophilic surfactants. Therefore, it wouldbe desirable to combine that advantage without the additionalcomplexities and costs.

Further to the above, a number of undesirable holes extending throughthe nonwoven webs, such as SMS webs, for example, may be created duringthe mechanical bonding process of various structures. Current equipmentand processes are not sufficient to bond combinations of SMS andspunbond (S, SS, SSS) materials at total basis weights below 25 gsmusing a pressure/shear bonding without an increase in the number ofholes created by the process. Holes are created from the bonding nubpunching through thin areas of the SMS or SS web. Increased holesthrough the bonded materials result in higher product failure rates(i.e., leakage). When an absorbent article that incorporates such anonwoven web is subsequently worn by a user, the presence of the holesmay result in undesirable leaks.

In view of the above, low cost nonwoven webs having low basis weights,adequate air permeability, (i.e., breathable), adequate tactilecharacteristics, and low surface tension fluid strikethrough timesexceeding certain parameters are desired. It is also desirable for thenonwoven materials to have more structural uniformity (i.e., less localbasis weight variation), especially at lower basis weights (e.g., lessthan 25 gsm, alternatively, less than 15 gsm, alternatively, less than13 gsm, and, alternatively, less than 10 gsm). An increased structuraluniformity in nonwoven webs of 25 gsm or less reduces the amount ofdefects (e.g., holes) created during mechanical bonding processes. Withspecific regard to barrier cuff materials, in one embodiment, it isdesired to have soft low basis weight webs with an improved barrieragainst low surface tension body exudates to give the absorbent coremore time to absorb the fluid, especially with recent and future trendof more “body-fitting” diaper designs and thinner absorbent cores.

As described in more detail below, a nonwoven component layer havingfine fibers (“N-fibers”) with an average diameter of less than 1 micron(an “N-fiber layer”) may be added to, or otherwise incorporated with,other nonwoven component layers to form a nonwoven web of material. Insome embodiments, the N-fiber layer may be used to produce a SNSnonwoven web or SMNS nonwoven web, for example. The N-fibers may becomprised of a polymer, e.g., selected from polyesters, including PETand PBT, polylactic acid (PLA), alkyds, polyolefins, includingpolypropylene (PP), polyethylene (PE), and polybutylene (PB), olefiniccopolymers from ethylene and propylene, elastomeric polymers includingthermoplastic polyurethanes (TPU) and styrenic block-copolymers (linearand radial di- and tri-block copolymers such as various types ofKraton), polystyrenes, polyamides, PHA (polyhydroxyalkanoates) and e.g.PHB (polyhydroxubutyrate), and starch-based compositions includingthermoplastic starch, for example. The above polymers may be used ashomopolymers, copolymers, e.g., copolymers of ethylene and propylene,blends, and alloys thereof. The N-fiber layer may be bonded to the othernonwoven component layers by any suitable bonding technique, such as thecalender bond process, for example, also called thermal point bonding.

In some embodiments, the use of an N-fiber layer in a nonwoven web mayprovide a low surface tension barrier that is as high as other nonwovenwebs that have been treated with a hydrophobic coating or a hydrophobicmelt-additive, and still maintain a low basis weight (e.g., less than 15gsm or, alternatively, less than 13 gsm). The use of the N-fiber layermay also provide a soft and breathable (i.e., air permeable) nonwovenmaterial that, at least in some embodiments, may be used in single weblayer configurations in applications which previously used double weblayer configurations. Furthermore, in some embodiments, the use of theN-fiber layer may at least reduce the undesirable migration ofhydrophilic surfactants toward the web and, therefore, may ultimatelyresult in better leak protection for an associated absorbent article.Also, when compared to an SMS web having a similar basis weight, the useof a nonwoven web comprising the N-fiber layer may decrease the numberof defects (i.e., holes or pinholes through the mechanical bond site)created during the mechanical bonding process.

Without intending to be bound by any particular theory, with regard tofluid barrier characteristics of the webs disclosed herein, it isbelieved that the small size of the pores created in the web by the useof the N-fiber layer along with the tightness or proximity of the fibersmay increase the hydrostatic pressure required to penetrate through thepores for low surface tension fluids and potentially increase capillarydrag forces. The fine pores may increase the capillary drag forcesapplied to a low surface tension fluid passing through the fine pores ofthe web to slow down low surface tension fluid strikethrough. Further,it is found that multiple aspects of the pore structure are relevant,more than the average pore size, such as, for example, the narrowness ofthe pore size distribution, mean-flow pore size, and modes of pore sizedistribution.

As discussed in more detail below, the webs of materials incorporatingthe N-fiber layer may be used in the construction of various absorbentarticles. In one embodiment, the absorbent articles of the presentdisclosure may comprise a liquid pervious topsheet, a backsheet attachedor joined to the topsheet, and an absorbent core disposed between thetopsheet and the backsheet. Absorbent articles and components thereof,including the topsheet, backsheet, absorbent core, and any individuallayers of these components, generally have an interior surface (orwearer-facing surface) and an exterior surface (or garment-facingsurface).

The following description generally discusses a suitable absorbent core,a topsheet, and a backsheet that may be used in absorbent articles, suchas disposable diapers, for example. It is to be understood that thisgeneral description applies to the components of the specific absorbentarticle shown in FIGS. 1, 2, and 3A-3B, which are further describedbelow, and to other absorbent articles which are described herein.

FIG. 1 is a plan view of an absorbent article 10 in accordance with onenon-limiting embodiment of the present disclosure. The absorbent article10 is illustrated in its flat, uncontracted state (i.e., with itselastic induced contraction removed for illustration and with portionsof the absorbent article 10 being cut-away to more clearly show theconstruction of the absorbent article 10. A portion of the absorbentarticle 10 which faces away from the wearer is oriented towards theviewer. FIG. 2 is a perspective view of the absorbent article 10 of FIG.1 in a partially contracted state. As shown in FIG. 1, the absorbentarticle 10 may comprise a liquid pervious first topsheet 20, a liquidimpervious backsheet 30 joined with the topsheet 20, and an absorbentcore 40 positioned between the topsheet 20 and the backsheet 30. Theabsorbent core 40 has an exterior surface (or garment-facing surface)42, an interior surface (or a wearer-facing surface) 44, side edges 46,and waist edges 48. In one embodiment, the absorbent article 10 maycomprise gasketing barrier cuffs 50 and longitudinal barrier cuffs 51.The longitudinal barrier cuffs 51, in some embodiments, may extendgenerally parallel to a central longitudinal axis 59. For example, thelongitudinal barrier cuffs 51 may extend substantially between the twoend edges 57. The absorbent article 10 may comprise an elastic waistfeature multiply designated as 60 (also referred to herein as awaistband or a belt) and a fastening system generally multiplydesignated as 70.

In one embodiment, the absorbent article 10 may have an outer surface52, an inner surface 54 opposed to the outer surface 52, a first waistregion 56, a second waist region 58, and a periphery 53 which is definedby longitudinal edges 55 and the end edges 57. (While the skilledartisan will recognize that an absorbent article, such as a diaper, isusually described in terms of having a pair of waist regions and acrotch region between the waist regions, in this application, forsimplicity of terminology, the absorbent article 10 is described ashaving only waist regions comprising a portion of the absorbent articlewhich would typically be designated as part of the crotch region). Theinner surface 54 of the absorbent article 10 comprises that portion ofthe absorbent article 10 which is positioned adjacent to the wearer'sbody during use (i.e., the inner surface 54 is generally formed by atleast a portion of the first topsheet 20 and other components that maybe joined to the topsheet 20). The outer surface 52 comprises thatportion of the absorbent article 10 which is positioned away from thewearer's body (i.e., the outer surface 52 is generally formed by atleast a portion of the backsheet 30 and other components that may bejoined to the backsheet 30). The first waist region 56 and the secondwaist region 58 extend, respectively, from the end edges 57 of theperiphery 53 to the lateral centerline (cross-sectional line 3-3) of theabsorbent article 10.

FIG. 2 shows a perspective view of the absorbent article 10 whichcomprises a pair of longitudinal barrier cuffs 51 in accordance with onenon-limiting embodiment of the present disclosure. FIG. 3 depicts across-sectional view taken along line 3-3 of FIG. 1.

In one embodiment, the absorbent core 40 may take on any size or shapethat is compatible with the absorbent article 10. In one embodiment, theabsorbent article 10 may have an asymmetric, modified T-shaped absorbentcore 40 having a narrowing of the side edge 46 in the first waist region56, but remaining generally rectangular-shaped in the second waistregion 58. Absorbent core construction is generally known in the art.Various absorbent structures for use as the absorbent core 40 aredescribed in U.S. Pat. No. 4,610,678, issued to Weisman et al., on Sept.9, 1986, U.S. Pat. No. 4,673,402, issued to Weisman, et al., on Jun. 16,1987, U.S. Pat. No. 4,888,231, issued to Angstadt, on Dec. 19, 1989, andU.S. Pat. No. 4,834,735, issued to Alemany et al., on May 30, 1989. Inone embodiment, the absorbent core 40 may comprise a dual core systemcontaining an acquisition/distribution core of chemically stiffenedfibers positioned over an absorbent storage core as described in U.S.Pat. No. 5,234,423, issued to Alemany, et al., on Aug. 10, 1993, andU.S. Pat. No. 5,147,345, issued to Young et al., on Sep. 15, 1992. Theabsorbent core 40 may also comprise a core cover 41 (as shown in FIGS.3A-B and as described in detail below) and a nonwoven dusting layer thatis disposed between the absorbent core 40 and the backsheet 30.

In one embodiment, the topsheet 20 of the absorbent article 10 maycomprise a hydrophilic material that promotes rapid transfer of fluids(e.g., urine, menses, and/or runny feces) through the topsheet 20. Thetopsheet 20 may be pliant, soft feeling, and non-irritating to thewearer's skin. Further, the topsheet may be fluid pervious, permittingfluids (e.g., menses, urine, and/or runny feces) to readily penetratethrough its thickness. In one embodiment, the topsheet 20 may be made ofa hydrophilic material or at least the upper surface of the topsheet maybe treated to be hydrophilic so that fluids will transfer through thetopsheet more rapidly and enter the absorbent core 40. This diminishesthe likelihood that body exudates will flow off of the topsheet 20rather than being drawn through the topsheet 20 and being absorbed bythe absorbent core 40. The topsheet 20 may be rendered hydrophilic bytreating it with a surfactant, for example. Suitable methods fortreating the topsheet 20 with a surfactant comprise spraying thetopsheet 20 with the surfactant and immersing the topsheet 20 into thesurfactant. A more detailed discussion of such a treatment is containedin U.S. Pat. No. 4,988,344, issued to Reising, on Jan. 29, 1991, andU.S. Pat. No. 4,988,345, issued to Reising, on Jan. 29, 1991.

In one embodiment, the backsheet 30 may be impervious, or at leastpartially impervious, to low surface tension fluids (e.g., menses,urine, and/or runny feces). The backsheet 30 may be manufactured from athin plastic film, although other flexible fluid impervious materialsmay also be used. The backsheet 30 may prevent, or at least inhibit, theexudates absorbed and contained in the absorbent core 40 from wettingarticles which contact the absorbent article 10, such as bedsheets,clothing, pajamas, and undergarments, for example. The backsheet 30 maycomprise a woven or a nonwoven web, polymeric films such asthermoplastic films of polyethylene or polypropylene, and/or compositematerials such as a film-coated nonwoven material or a film-nonwovenlaminate. In one embodiment, a suitable backsheet 30 may be apolyethylene film having a thickness of from 0.012 mm (0.5 mils) to0.051 mm (2.0 mils). Exemplary polyethylene films are manufactured byClopay Corporation of Cincinnati, Ohio, under the designation P18-1401and by Tredegar Film Products of Terre Haute, Ind., under thedesignation XP-39385. The backsheet 30 may be embossed and/or mattefinished to provide a more cloth-like appearance. Further, the backsheet30 may permit vapors to escape from the absorbent core 40 (i.e., thebacksheet 30 is breathable and has an adequate air permeability), whilestill preventing exudates from passing through the backsheet 30. Thesize of the backsheet 30 may be dictated by the size of the absorbentcore 40 and the exact absorbent article design selected. In oneembodiment, the backsheet 30 may comprise an SNS and/or an SMNS web, asdescribed in greater detail below.

Other optional elements of the absorbent article 10 may comprise afastening system 70, elasticized side panels 82, and a waist feature 60.The fastening system 70 allows for the joining of the first waist region56 and the second waist region 58 in an overlapping configuration suchthat lateral tensions are maintained around the circumference of theabsorbent article 10 to maintain the absorbent article 10 on the wearer.Exemplary fastening systems 70 are disclosed in U.S. Pat. No. 4,846,815,issued to Scripps, on Jul. 11, 1989, U.S. Pat. No. 4,894,060, issued toNestegard, on Jan. 16, 1990, U.S. Pat. No. 4,946,527, issued toBattrell, on Aug. 7, 1990, U.S. Pat. No. 3,848,594, issued to Buell, onNov. 19, 1974, U.S. Pat. No. 4,662,875, issued to Hirotsu et al., on May5, 1987, and U.S. Pat. No. 5,151,092, issued to Buell et al., on Sep.29, 1992. In certain embodiments, the fastening system 70 may beomitted. In such embodiments, the waist regions 56 and 58 may be joinedby the absorbent article manufacturer to form a pant-type diaper havinga preformed waist opening and leg openings (i.e., no end-usermanipulation of the diaper is needed to form the waist opening and legopenings). Pant-type diapers are also commonly referred to as “closeddiapers,” “prefastened diapers,” “pull-on diapers,” “training pants,”and “diaper-pants”. Suitable pants are disclosed in U.S. Pat. No.5,246,433, issued to Hasse et al., on Sep. 21, 1993, U.S. Pat. No.5,569,234, issued to Buell et al., on Oct. 29, 1996, U.S. Pat. No.6,120,487, issued to Ashton, on Sep. 19, 2000, U.S. Pat. No. 6,120,489,issued to Johnson et al., on Sep. 19, 2000, U.S. Pat. No. 4,940,464,issued to Van Gompel et al., on Jul. 10, 1990, and U.S. Pat. No.5,092,861, issued to Nomura et al., on Mar. 3, 1992. Generally, thewaist regions 56 and 58 may be joined by a permanent or refastenablebonding method.

In certain embodiments, the absorbent article 10 may comprise at leastone barrier member. In one embodiment, barrier members are physicalstructures joined to, applied to, and/or formed with the absorbentarticle 10 to improve the barrier properties of the absorbent article10. In one embodiment, barrier members may comprise structures such as acore cover, an outer cover, a longitudinal barrier cuff, a gasketingcuff, an elasticized topsheet, and combinations thereof. It may bedesirable that a barrier member comprise the SNS web and/or the SMNSweb, as described in further detail below.

In one embodiment, the absorbent article 10 may comprise one or morelongitudinal barrier cuffs 51 which may provide improved containment offluids and other body exudates. The longitudinal barrier cuffs 51 mayalso be referred to as leg cuffs, barrier leg cuffs, longitudinal legcuffs, leg bands, side flaps, elastic cuffs, or “stand-up” elasticizedflaps. Elasticity may be imparted to the longitudinal barrier cuffs 51by one or more elastic members 63. Elastic members 63 may provideelasticity to the longitudinal barrier cuff 51 and may aid in keepinglongitudinal barrier cuff 51 in a “stand-up” position. U.S. Pat. No.3,860,003, issued to Buell, on Jul. 14, 1975, describes a disposablediaper that provides a contractible leg opening having a side flap andone or more elastic members to provide an elasticized leg cuff. U.S.Pat. Nos. 4,808,178 and 4,909,803 issued to Aziz et al. on Feb. 28, 1989and Mar. 20, 1990, respectively, describe absorbent articles comprising“stand-up” elasticized flaps that improve the containment at the legregions of the absorbent article 10. Additionally, in some embodiments,the one or more longitudinal barrier cuffs 51 may be intergral with oneor more gasketing cuffs 50. For example, the longitudinal barrier cuffs51 and the gasketing cuffs 50 may be formed from a single web ofmaterial, as illustrated in FIGS. 3A-3B. As with the longitudinalbarrier cuffs 51, the gasketing cuffs 50 may comprises one or moreelastic members 62.

FIGS. 3A-B shows a cross-sectional view of the absorbent article 10 ofFIG. 1 taken along line 3-3. FIGS. 3A-B depict various cuffconstructions; however, modifications may be made to the cuffconstruction without departing from the spirit and scope of the presentdisclosure. A gasketing cuff 50 and a longitudinal barrier cuff 51 areboth shown in FIGS. 3A-B, but a single cuff design is equally feasible.FIG. 3A illustrates a gasketing cuff 50 and a longitudinal barrier cuff51 construction in accordance with one non-limiting embodiment. Bothcuffs 50, 51 may share a common web 65, such as an SNS web or an SMNSweb, for example. The longitudinal barrier cuff 51 is shown in a singlelayer configuration where over a substantial portion of the lateralwidth of the longitudinal barrier cuff 51 comprises a single ply of theweb 65. FIG. 3B illustrates a gasketing cuff 50 and longitudinal barriercuff 51 construction with the longitudinal barrier cuff 51 in a multiplelayer configuration in accordance with another non-limiting embodiment.In the multiple layer construction, at least two plys of the web (suchas an SNS web or an SMNS web, for example) exist over a substantialportion of the lateral width of the longitudinal barrier cuff 51. Thoseof skill in the art will recognize that the exact configuration of theweb 65 may be altered in various embodiments.

A variety of suitable materials may be used as the web 65 in the cuffsdescribed above. Suitable embodiments may have the web 65 comprising aplurality of layers, such as two spunbond layers and at least oneN-fiber layer disposed between the two spunbond layers, for example, asdescribed in greater detail below. Some embodiments of the web 65 maycomprise a hydrophobic material, as described in greater detail below.

As shown in FIGS. 3A-B, a core cover 41 may be included in certainembodiments of the absorbent article 10 to provide structural integrityto the absorbent core 40. The core cover 41 may contain the absorbentcore 40 components such as cellulosic material and absorbent gellingmaterial, which both may tend to migrate, move, or become airbornewithout a physical barrier. The core cover 41 may entirely envelop thecore 40, as shown in FIGS. 3A-B, or may partially cover the absorbentcore 40. The core cover 41 may generally comprise a nonwoven web. Incertain embodiments, the core cover 41, or other components of theabsorbent article 10, may comprise an SNS web and/or an SMNS web.

In certain embodiments, the absorbent article 10 may comprise an outercover 31. The outer cover 31 may cover all of, or substantially all of,the exterior surface of the absorbent article 10. In some embodiments,the outer cover 31 may be coterminous with the backsheet 30. The outercover 31 may be bonded to a portion of the backsheet 30 to form alaminate structure. Bonding may be performed by any conventionalmethods, such as adhesive bonding, mechanical bonding, and thermalbonding, for example. The outer cover 31 may be utilized to provideextra strength or bulk to the absorbent article 10. Outer covers 31 areoften used to improve the aesthetic quality of the exterior surface ofthe absorbent article 10. It is also desirable that the exterior surfaceof the absorbent article 10 exhibit a cloth-like look and feel, as suchfeatures are pleasing to consumers. Various materials are suitable foruse as the outer cover 31. Such materials comprise woven webs, foams,scrims, films, and loose fibers. However, in certain embodiments, theouter cover 31 may be constructed to provide increased barrierprotection. In certain embodiments, the outer cover 31 may comprise anSNS web and/or an SMNS web.

FIG. 4 shows a schematic diagram of a forming machine 110 used to make anonwoven web 112, such as an SNS web or an SMNS web, for example, inaccordance with one embodiment. To make an SMNS web, the forming machine110 is shown as having a first beam 120 for producing first coarsefibers 135, an optional second beam 121 for producing intermediatefibers 127 (e.g., meltblown fibers), a third beam 122 for producing finefibers 131 (e.g., N-fibers), and a fourth beam 123 for producing secondcoarse fibers 124. The forming machine 110 may comprise an endlessforming belt 114 which travels around rollers 116, 118 so the formingbelt 114 is driven in the direction as shown by the arrows 114. Invarious embodiments, if the optional second beam 121 is utilized, it maybe positioned intermediate the first beam 120 and the third beam 122 (asillustrated), or may be positioned intermediate the third beam 122 andthe fourth beam 124, for example.

In one embodiment, the first beam 120 may produce first coarse fibers135, such as by use of a conventional spunbond extruder with one or morespinnerets which form continuous fibers of polymer. Forming spunbondfibers and the design of such a spunbond forming first beam 120 iswithin the ability of those of skill in the art. Spunbond machines maybe acquired from Reicofil GmbH in Troisdorf, Germany, for example.Suitable thermoplastic polymers comprise any polymer suitable forspunbonding such as polyesters, including PET and PBT, polylactic acid(PLA), and alkyds, polyolefins, including polypropylene (PP),polyethylene (PE), and polybutylene (PB), olefinic copolymers fromethylene and propylene, elastomeric polymers including thermoplasticpolyurethanes (TPU) and styrenic block-copolymers (linear and radial di-and tri-block copolymers such as various types of Kraton), polystyrenes,polyamides, PHA (polyhydroxyalkanoates) and e.g. PHB(polyhydroxubutyrate), and starch-based compositions includingthermoplastic starch, for example. The above polymers may be used ashomopolymers, copolymers, e.g., copolymers of ethylene and propyelene,blends, and alloys thereof. The polymer is heated to become fluid,typically at a temperature of 100-350° C., and is extruded throughorifices in the spinneret. The extruded polymer fibers are rapidlycooled and attenuated by air streams to form the desired denier fibers.The first coarse fibers 135 resulting from the first beam 120 may bedispensed or laid onto the forming belt 114 to create a first nonwovencomponent layer 136. The first nonwoven component layer 136 may beproduced from multiple beams or spinnerets of the type of the first beam120, but still creates one nonwoven component layer when the fibersproduced from the multiple beams or spinnerets are of the same diameter,shape, and composition. The first beam 120 may comprise one or morespinnerets depending upon the speed of the process or the particularpolymer being used. The spinnerets of the first beam 120 may haveorifices with a distinct shape that imparts a cross-sectional shape tothe first coarse fibers 135. In one embodiment, the spinnerets may beselected to yield fibers with cross-sectional shapes including, but notlimited to, circular, oval, rectangular, square, triangular, hollow,multi-lobal, irregular (i.e., nonsymmetrical), and combinations thereof.

In one embodiment, the second beam 121, if used, may produceintermediate diameter fibers 127, such as meltblown fibers, for example.The meltblown process results in the extrusion of a thermoplasticpolymer through a die 119 containing a plurality of orifices. In someembodiments, the die 119 may contain from 20 to 100, or even more,orifices per inch of die width. As the thermoplastic polymer exits thedie 119, high pressure fluid, usually hot air may attenuate and spreadthe polymer stream to form the intermediate fibers 127. The intermediatefibers 127 resulting from the second beam 121 may be dispensed or laidonto the first nonwoven component layer 136 carried by the forming belt114, to create a fourth nonwoven component layer 128. The forth nonwovencomponent layer 128 may be produced from multiple, adjacent beams of thetype like the second beam 121.

In one embodiment, the third beam 122 may produce the fine fibers 131(i.e., N-fibers). In some embodiments, the N-fibers may be producedusing systems and melt film fibrillation methods described in U.S. Pat.Nos. 6,315,806, 5,183,670, and 4,536,361, to Torobin et al., and U.S.Pat. Nos. 6,382,526, 6,520,425, and 6,695,992, to Reneker et al. andassigned to the University of Akron. Other melt film fibrillationmethods and systems are described in the U.S. Pat. Publ. No.2008/0093778, to Johnson, et al., published on Apr. 24, 2008, U.S. Pat.No. 7,628,941, to Krause et al., and U.S. Pat. Publ. No. 2009/0295020,to Krause, et al., published on Dec. 3, 2009 and provide uniform andnarrow fiber distribution, reduced or minimal fiber defects such asunfiberized polymer melt (generally called “shots”), fly, and dust, andfurther provide uniform N-fibers layer 132 for absorbent articles, suchas those described by the present disclosure. The improvements in themelt film fibrillation method, specifically the design ofconverging-diverging gas passage specifications and the fluid curtain,described by the Johnson et al. and Krause et al., respectively, mayprovide the N-fibers of desired structural attributes such asnumber-average fiber diameter distribution, mass-average fiber diameterdistribution, pore-size distribution, and structural uniformity (i.e.,less local basis weight variation) for the embodiments of the presentdisclosure as described herein. Generally, in one embodiment, apressurized gas stream flows within a gas passage confined between firstand second opposing walls, which define respective upstream convergingand downstream diverging wall surfaces. A polymer melt is introducedinto the gas passage to provide an extruded polymer film on the heatedwall surfaces that is impinged by the gas stream flowing within the gaspassage, effective to fibrillate the polymer film into sub-microndiameter fibers or fibers. The fine fibers 131 may then be dispensed orlaid onto the first nonwoven component layer 136 to create the secondnonwoven component layer 132. In some embodiments, such as during theproduction of an SMNS web, for example, the fine fibers 131 may bedispensed or laid onto the fourth nonwoven component layer 128, which iscarried on the forming belt 114. Alternatively, in some embodiments, thefine fibers 131 may be laid onto the first nonwoven component layer 136and subsequently the intermediate fibers 127, such as meltblown fibers,may be laid onto the layer of fine fibers 131. The fine fiber layer 132may be produced from more than one beam of the type of the third beam122.

In one embodiment, the fourth beam 123 (or multiple beams like 120) mayproduce the second coarse diameter fibers 124 that are similar to thefirst coarse fibers 135. The second coarse fibers 124 may be dispensedor laid onto the second nonwoven component layer 132 of the web 112,such as during the production of an SNS web, for example. The resultingweb 112 may be fed through thermal bonding rolls 138, 140. The bondingrolls 138, 140 are commonly referred to as a calender. The surfaces ofone or both of the bonding rolls 138, 140 may be provided with a raisedpattern or portions such as spots, grids, pins, or nubs, for example. Inone embodiment, the bonding rolls 138, 140 may be heated to thesoftening temperature of the polymer used to form the nonwoven componentlayers of the web 112. As the web 112 passes between the heated bondingrolls 138, 140, the nonwoven component layers may be embossed by thebonding rolls 138, 140 in accordance with the pattern on the bondingrolls 138, 140 to create a pattern of discrete areas, such as calenderbond 168 shown in FIG. 5. The discrete areas are bonded from nonwovencomponent layer to nonwoven component layer with respect to theparticular fibers within each layer. Such discrete area, or calenderbond site, may be carried out by heated rolls or by other suitabletechniques. Another thermal fiber bonding technique comprises blowinghot air through the web 112. Air-through bonding techniques maygenerally be used with low melting point matrix fibers, biocomponentfibers, and powders. While a nonwoven web is described herein ascomprising three to four nonwoven component layers, any suitable numberof nonwoven component layers may be used and are within the scope of thepresent disclosure.

FIG. 5 illustrates a cross-sectional view of an SNS web at a calenderbond site 168 in accordance with one non-limiting embodiment. A threelayer nonwoven web 112 is illustrated that was produced by the formingmachine 110 described above without the optional second beam 121 (e.g.,the meltblown layer). The nonwoven web 112 may comprise a first nonwovencomponent layer 125 which itself may be comprised of coarse fibers, suchas spunbond fibers, for example. In one embodiment, the first nonwovencomponent layer 125 may comprise fibers having an average diameter,alternatively, number-average diameter, in the range of 8 microns to 30microns and, alternatively, in the range of 10 microns to 20 microns,with a relative standard deviation in the range of 4% to 10%. Statedanother way, the first nonwoven component layer 125 may comprise fibershaving an average denier in the range of 0.4 to 6.0, with a relativestandard deviation in the range of 8% to 15%. The mass-average fiberdiameter in the same embodiment may be in the range of 8 microns to 30microns and, alternatively, in the range of 10 microns to 20 microns,with a relative standard deviation in the range of 4% to 10%. In oneembodiment, the first nonwoven component layer 125 may have a basisweight in the range of 1 gsm to 10 gsm and, alternatively, in the rangeof 2 gsm to 7 gsm, e.g., 5.5 gsm. In certain embodiments, the fibers inthe first nonwoven component layer 125 may have non-circularcross-sections, such as trilobal cross-sections, for example, or may bebicomponent fibers, such as sheath-core or side by side, for example.

In one embodiment, the nonwoven web 112 may comprise a second nonwovencomponent layer 132 which itself may be comprised of fine fibers, suchas N-fibers. In one embodiment, the second nonwoven component layer 132may comprise fine fibers having a number-average diameter (alternatively“average diameter”) less than 1 micron, alternatively, in the range of0.1 microns to 1 micron, alternatively in the range of 0.2 microns to0.9 microns, alternatively in the range of 0.3 microns to 0.8 micronsand, alternatively, in the range of 0.5 microns to 0.7 microns, with arelative standard deviation of less than 100%, alternatively less than80%, alternatively less than 60%, alternatively less than 50%, such asin the range of 10% to 50%, for example; and with over 80%, such as over90%, or 95 to 100%, for example, of the fibers having less than 1 microndiameter, i.e. submicron. The mass-average diameter of fibers in thesecond nonwoven component layer 132 may be less than 2 microns,alternatively, in the range of 0.1 micron to 2 microns, alternatively,in the range of 0.1 microns to 1.5 microns, alternatively, in the rangeof 0.1 microns to 1 micron, alternatively, in the range of 0.2 micronsto 0.9 microns, alternatively, in the range of 0.3 microns to 0.8microns and, alternatively, in the range of 0.5 microns to 0.7 microns,with a relative standard deviation of less than 100%, alternatively lessthan 80%, alternatively less than 60%, alternatively less than 50%, suchas in the range of 10% to 50%, for example. Stated another way, thesecond nonwoven component layer 132 may comprise fine fibers having anaverage denier in the range of 0.00006 to 0.006, alternatively, in therange of 0.0002 to 0.005, alternatively, in the range of 0.0016 to0.005, and alternatively, in the range of 0.002 to 0.004, with arelative standard deviation in the range of less than 200%,alternatively, less than 150%, and alternatively, less than 120%; andwith over 80%, alternatively, over 90%, and alternatively, 95 to 100% ofthe fibers less than 0.006 denier.

In an embodiment with the mass-average fiber distribution of less than 1micron, almost all the fibers must have a diameter less than 1 micron.Even with very few fibers above 1 micron, it would make the mass-averagefiber diameter greater than 1 micron. Thicker fibers have larger mass;thus, the presence of thicker fibers with larger mass increases themass-average fiber diameter more than the number-average fiber diameteras described in the Fiber Diameter Calculations set forth below. Forexample, a fiber with a diameter of 3 microns (a typical meltblownfiber) has 36 times more mass than a submicron N-fiber of the samelength and with a typical diameter of 0.5 microns because the 3 micronfiber has a cross-sectional area 36 times larger than that of a 0.5micron diameter fiber. Alternatively, a single 3 micron fiber diameterfiber may take the place of 36 fibers of 0.5 micron diameter, andincrease the mass-average fiber diameter of the second component layer.Conversely, to reduce the mass-average fiber diameter, it is critical toreduce the number of fibers with diameter greater than 1 micron. In oneembodiment, the second nonwoven component layer may comprise fibershaving a number-average diameter of less than 1 micron, a mass-averagediameter of less than 1.5 microns, and a ratio of the mass-averagediameter to the number-average diameter less than 2. In someembodiments, the second nonwoven component layer may comprise fibershaving a number-average diameter of less than 1 micron, a mass-averagediameter of less than 1 micron, and a ratio of the mass-average diameterto the number-average diameter less than 1.5, for example.

Without intending to be bound by any particular theory, it is believedthat the finer fibers make finer pores in the nonwoven web. As set forthherein, the finer pores provide greater fluid strikethrough performanceof the nonwoven web. Therefore, it is desirable to have as many finefibers as possible in the nonwoven web to improve low surface tensionfluid strikethrough times. By reducing the number of thicker fibers andincreasing the number of fine fibers less than 1 micron in the N-layer,the embodiments of the present disclosure achieve finer pore sizes andhigher low surface tension fluid strikethrough times than conventionalwebs. In one embodiment, the mean-flow pore diameter in the secondcomponent layer 132 may be less than 20 micron, alternatively less than15 micron, alternatively less than 10 micron, and alternatively lessthan 5 micron. The mean-flow pore diameter corresponds to the pressure(called mean-flow pressure) below which half the flow happens, while therest half of the flow happens above that pressure. Since pore diameterand pressure are inversely related, smaller mean-flow pore diametersuggests higher mean-flow pressure or flow resistance that slows downthe flow, and increases the fluid strikethrough time. Because themean-flow pore diameter is a flow attribute of a structure it isdistinct from the average pore diameter that is just a statisticalnumber average of pore diameter distribution, and the average porediameter may not correlate to any fixed flow attribute. Alternatively,the average pore diameter may not necessarily become smaller as themean-flow pore diameter becomes smaller, e.g, as the fiber diameter isreduced. It is believed that it is critical for an embodiment of thepresent disclosure to have the mean-flow pore diameter in the secondcomponent layer 132 less than 20 micron, alternatively less than 15micron, alternatively less than 10 micron, and alternatively less than 5micron.

The pore size distribution of the nonwoven web of the present disclosuremay have one or more peaks or modes (where the mode of a pore sizedistribution is defined as the pore size value with highest frequency)corresponding to the multiple component layers. In one embodiment, thepore size corresponding to the lowest or the first mode of the pore sizedistribution corresponds to the second component layer 132 comprisingN-fibers. In such embodiment, the lowest or the first mode of the poresize distribution may be less than 15 micron, alternatively less than 10micron, and alternatively 5 micron or less. As described above, smallerpore diameter suggests higher resistance to the flow, and accordinglygreater fluid strikethrough time. In some embodiments, the diametercorresponding to the lowest mode (corresponding to the smallest fibers)blocks the last 20% or more of the fluid flow (that is the porediameters larger than the lowest mode allow the 80% or less of the fluidflow). Therefore, it is believed that the smallest pores, the highertheir number the better, provide the highest resistance to the flow, andincrease fluid strikethrough time.

The porosity of the second component layer 132 may be greater than 50%,alternatively greater than 70%, and alternatively greater than 80%.Since porosity corresponds to the void volume through which flow mayhappen, lower porosity resists the flow, and accordingly increases theliquid strikethrough time. The second component layer 132 may have atleast 50% fibers with the number-average diameter less than 1 micron,alternatively at least 70% fibers with the number-average diameter lessthan 1 micron, alternatively at least 80% fibers with the number-averagediameter less than 1 micron, and alternatively at least 90% fibers withthe number-average diameter less than 1 micron. Nonwoven structures witha significant number of fibers of diameter less than 1 micron have beendescribed by Isele et al. in U.S. Pat. Publ. Nos. 2006/0014460 publishedon Jan. 1, 2006, and 2005/0070866 published Mar. 31, 2005, both assignedto The Procter and Gamble Company, using the methods described byTorobin et al. and Reneker et al. However, having even more than 90%fibers with diameter less than 1 micron in the second nonwoven componentlayer 132 is not sufficient (but necessary) to have the mass-averagediameter less than 1 micron, even though the number-average diameter maybe less than 1 micron as described herein. In one embodiment, the secondnonwoven component layer 132 may have at least 99% of fibers with thenumber-average diameter less than 1 micron. Therefore, in an embodimentof the present disclosure with the second nonwoven component layer 132comprising fibers with the mass-average diameter less than 1 micron andthe number-average fiber diameter less than 1 micron, almost all thefibers may have a diameter less than 1 micron, alternatively all thefibers of the second nonwoven component layer 132 in such an embodimentare submicron.

The polydispersity of fiber diameter distribution, defined as the ratioof the mass-average diameter to the number-average diameter, of thefibers comprising the second nonwoven component layer 132 may be lessthan 2, alternatively less than 1.8, alternatively less than 1.5,alternatively less than 1.25, alternatively less than 1.1, andalternatively 1.0. The polydispersity of fiber diameter distributionmeasures the width of fiber distribution. The higher the value of thepolydispersity of the distribution, the wider is the distribution. Inone embodiment, as the polydispersity approaches 1, that is, themass-average and number-average fiber diameters are the same, the secondnonwoven component layer 132 may have an extremely uniform and narrowfiber distribution. The arithmetic difference between the mass-averagediameter and the number-average diameter may be less than one standarddeviation of the number-average diameter, alternatively, the differencemay be less than three-fourths of one standard deviation of thenumber-average diameter, alternatively, the difference may be less thanone-half of one standard deviation of the number-average diameter.Because of the above-mentioned fiber diameter averages andpolydispersity of fiber diameter distribution, the N-fibers in thesecond nonwoven component layer 132 of the present disclosure differfrom typical ultra-fine meltblown fibers that may also have thenumber-average diameter less than 1 micron, but typically have themass-average diameter greater than 1 micron, and even greater than 2microns or higher due to presence of a finite number of fibers with thediameter greater than 1 micron. As mentioned above, even withsignificantly large percentage of fibers, alternatively greater than 90%of fibers, having a diameter less than 1 micron, the ultra-finemeltblown fibers may not have the mass-average diameter near or lessthan 1 micron. The difference between the mass-average and thenumber-average diameters of the ultra-fine fibers may be greater thanone-half of one standard deviation of the number-average diameter, moretypically, the difference may be greater than one standard deviation ofthe number-average diameter, alternatively, the difference may begreater than two standard deviations of the number-average diameter ofthe ultra-fine meltblown fibers. In one embodiment, the second nonwovencomponent layer 132 may have a basis weight in the range of 0.1 gsm to10 gsm, alternatively, in the range of 0.2 gsm to 5 gsm, alternatively,in the range of 0.5 to 3 gsm, and, alternatively 1 to 1.5 gsm.

In one embodiment, the nonwoven web 112 may comprise a third nonwovencomponent layer 136 which itself is comprised of coarse fibers, such asspunbond fibers, and may be similar to the first nonwoven componentlayer 125.

If the fourth nonwoven component layer 128 is used, such as a meltblownlayer, these intermediate diameter fibers may comprise fibers having anaverage diameter, alternatively number-average diameter, in the range of0.7 microns to 8 microns, alternatively in the range of 1 micron to 8microns, and, alternatively, in the range of 1 micron to 5 microns, witha relative standard deviation in the range of 20% to over 100%. Themass-average diameter of the fourth nonwoven component layer 128, suchas a meltblown layer, may be in range of 0.7 microns to 8 microns,alternatively in the range of 1 micron to 8 microns, and, alternatively,in the range of 1 micron to 5 microns, and alternatively in the range of2 to 5 micron, with a relative standard deviation in the range of 20% toover 100%. In addition, the polydispersity of the fiber diameters in theintermediate fiber layer is in the range from 1 to 10, alternativelyfrom 2 to 8, alternatively from 2 to 6, alternatively from 1.5 to 5.Stated another way, the fourth nonwoven component layer 128 may comprisefibers having an average denier in the range of 0.003 to 0.4,alternatively, in the range of 0.006 to 0.3, with a relative standarddeviation of in the range of 50% to 600%, alternatively in the range of150% to 300%. In one embodiment, the meltblower layer may have a basisweight in the range of 0.1 gsm to 10 gsm, alternatively, in the range of0.2 gsm to 5 gsm, and, alternatively, in the range of 0.5 gsm to 3 gsmand, alternatively, in the range of 1 to 1.5 gsm.

Also, the intermediate and fine diameter fibers may be of a bicomponentor polymer blend type, for example.

In one embodiment, referring to FIGS. 1-3, the absorbent article 10 maybe configured to be worn about a lower torso of a wearer. In variousembodiments, the absorbent article 10 may comprise a chassis 47comprising a topsheet 20, a backsheet 30, and an absorbent core 40disposed between, or at least partially between, the topsheet 20 and thebacksheet 30. A pair of longitudinal barrier cuffs 51 may be attached toand/or formed with a portion of the chassis 47, such as the topsheet 20,for example. Each longitudinal barrier cuff 51 may be formed of a web ofmaterial, such as an SNS web or an SMNS web. In one embodiment, the webof material may be formed of a plurality of nonwoven component layersarranged in various combinations and permutations of a plurality ofspunbond, meltblown, and N-fiber layers, including but not limited toSMN, SMNMS, SMMNMS, SSMMNS, SSNNSS, SSSNSSS, SSMMNNSS, SSMMNNMS, and thelike. The webs of material disclosed herein exhibit exceptional,unexpected properties when compared to related webs of material asdescribed in further detail below.

In one embodiment, referring to FIGS. 5 and 6, a web of material 112 maycomprise a first nonwoven component layer 125 comprising fibers havingan average diameter in the range of 8 microns to 30 microns, a secondnonwoven component layer 132 comprising fibers having a number-averagediameter of less than 1 micron, a mass-average diameter of less than 1.5micron, and a polydispersity ratio less than 2, and a third nonwovencomponent layer 136 comprising fibers having an average diameter in therange of from 8 microns to 30 microns. Stated another way, the web ofmaterial 112 may comprise the first nonwoven component layer 125comprising fibers having an average denier in the range of 0.4 to 6, thesecond nonwoven component layer 132 comprising fibers having an averagedenier in the range of 0.00006 to 0.006, and a third nonwoven componentlayer 136 comprising fibers having an average denier in the range of 0.4to 6. In such an embodiment, the second nonwoven component layer 132 maybe disposed intermediate the first nonwoven component layer 125 and thethird nonwoven component layer 136. Also, the first nonwoven componentlayer 125, the second nonwoven component layer 132, and the thirdnonwoven component layer 136 may be intermittently bonded to each otherusing any suitable bonding process, such as a calendering bondingprocess, for example. In one embodiment, the web of material 112 doesnot comprise a film. In various embodiments, the web of material 112 maycomprise a spunbond layer, which may correspond to the first nonwovencomponent layer 125, an N-fiber layer, which may correspond to thesecond nonwoven component layer 132, and a second spunbond layer, whichmay correspond to the third nonwoven component layer 136, togetherreferred to herein as an “SNS web.”

SMS (spunbond-meltblown-spunbond) webs may have pore sizes whichsometimes allow low surface tension fluids to penetrate therethroughafter a particular increment of time. Some photographs of such SMS websare illustrated in FIGS. 7 and 8. FIG. 7 is a top view of an 13 gsm SMSweb 215 at 500 times magnification. FIG. 8 is a cross-sectional view ofthe SMS web 215 of FIG. 7 taken through a calendering bond site in theSMS web at 500 times magnification. Non-limiting example photographs,which are taken using a scanning electron microscope (SEM), of an 15 gsmSNS web 212 are illustrated in FIGS. 9 and 10. FIG. 9 is a top view ofthe SNS web 212 at 200 times magnification. FIG. 10 is a cross-sectionalview of the SNS web 212 of FIG. 9 taken through a calendering bond sitein the SNS web 212 at 500 times magnification. In one embodiment, otherconfigurations (i.e., layering patterns) of the web of material 212 areenvisioned and are within the scope of the present disclosure, such as aweb of material comprising a spunbond layer, an N-fiber layer, a secondspunbond layer, and a third spunbond layer of different composition orfiber cross-section, for example.

In one embodiment, a web of material, such as the SNS web 212, forexample, may have a total basis weight of less than 30 gsm,alternatively, less than 15 gsm, alternatively, e.g., 13 gsm,alternatively, less than 10 gsm, and alternatively, in the range of 7gsm to 15 gsm. In such an embodiment, the web of material may notcomprise a film and has an air permeability of at least 1 m³/m²/min,alternatively, at least 10 m³/m²/min, alternatively, at least 20m³/m²/min, an alternatively, at least 40 m³/m²/min but less than 100m³/m²/min. In one embodiment, the web of material may have a local basisweight variation of less than 10%, alternatively, less than 8%, andalternatively, less than 6%, and a 32 mN/m low surface tension fluidstrikethrough time of at least 19 seconds, alternatively, at least 23seconds, alternatively, at least 30 seconds, alternatively, at least 35seconds, alternatively, at least 40 seconds, alternatively, at least 45seconds, and alternatively, at least 50 seconds.

In one embodiment, referring to FIGS. 11 and 12, a web of material 212′may comprise a first nonwoven component layer 225′ comprising fibershaving an average diameter in the range of 8 microns to 30 microns, asecond nonwoven component layer 232′ comprising fibers having a numberaverage diameter of less than 1 micron, a mass-average diameter of lessthan 1.5 micron, and a polydispersity ratio less than 2, a thirdnonwoven component layer 236′ comprising fibers having an averagediameter in the range of 8 microns to 30 microns, and a fourth nonwovencomponent layer 228′ comprising fibers having an average diameter in therange of 1 micron to 8 microns. Stated another way, the web of material212′ may comprise the first nonwoven component layer 225′ comprisingfibers having an average denier in the range of 0.4 to 6, the secondnonwoven component layer 232′ comprising fibers having an average denierin the range of 0.00006 to 0.006, a third nonwoven component layer 236′comprising fibers having an average denier in the range of 0.4 to 6, anda fourth nonwoven component layer 228′ comprising fibers having anaverage denier in the range of 0.006 to 0.4. In such an embodiment, thesecond nonwoven component layer 232′ and the fourth nonwoven componentlayer 228′ may be disposed intermediate the first nonwoven componentlayer 225′ and the third nonwoven component layer 236′. Also, the firstnonwoven component layer 225′, the second nonwoven component layer 232′,the third nonwoven component layer 236′, and the fourth nonwovencomponent layer 228′ may be intermittently bonded to each other usingany bonding process, such as a calendering bonding process, for example.In one embodiment, the web of material 212′ does not comprise a film. Invarious embodiments, the web of material 212′ may comprise a spunbondlayer, which may correspond to the first nonwoven component layer 225′,a meltblown layer, which may correspond to the fourth nonwoven componentlayer 228′, an N-fiber layer, which may correspond to the secondnonwoven component layer 232′ and a second spunbond layer, which maycorrespond to the third nonwoven component layer 236′, together referredto herein as an “SMNS web.” Non-limiting example photographs, which aretaken using a scanning electron microscope, of an SMNS web 212″ areillustrated in FIGS. 13 and 14. FIG. 13 is a top view of the SMNS web212″ at 1000 times magnification. FIG. 14 is a cross-sectional view ofthe SMNS web 212″ of FIG. 13 at 500 times magnification. In oneembodiment, other configurations of webs of material are envisioned andare within the scope of the present disclosure, such as a web ofmaterial comprising a spunbond layer, a meltblown layer, an N-fiberlayer, a second spunbond layer, and a third spunbond layer of differentstructure or composition, for example.

In one embodiment, referring to FIG. 1, the chassis 47 may define thetwo end edges 57, and the central longitudinal axis 59 may be defined inthe chassis 47 and extend from one midpoint of an end edge 57 to themidpoint of the other end edge 57. In various embodiments, referring toFIGS. 1, 3A, 11 and 12, the third nonwoven component layer 236′ may bepositioned most proximal to the central longitudinal axis 59, the firstnonwoven component layer 225′ may be positioned most distal from thecentral longitudinal axis 59, and the second nonwoven component layer232′ may be disposed intermediate the third nonwoven component layer236′ and the fourth nonwoven component layer 228′. FIG. 3A comprises anexploded portion of the web 212′ which illustrates this configuration.In certain other embodiments, the fourth nonwoven component layer 228′may be disposed intermediate the third nonwoven component layer 236′ andthe second nonwoven component layer 232′, for example. It is possible todetermine where the second nonwoven component layer 232′ and/or thefourth nonwoven component layer 228′ are positioned within a web usingan SEM. In general, low surface tension fluid strikethrough times appearto improve by 10% to 15%, for example, when the second nonwovencomponent layer 232′ is positioned closer to the skin of the wearer(i.e., closer to the central longitudinal axis 59 of the absorbentarticle 10). This is referred to as “sidedness.”In one embodiment, bypositioning the second nonwoven component layer 232′ closer to thecentral longitudinal axis 59 than the fourth nonwoven component layer228′, the second nonwoven component layer 232′ is positioned closer tothe skin of the wearer when the absorbent article 10 is positioned aboutthe lower torso of the wearer. Without intending to be bound by anyparticular theory, applicants believe that the SMNS web exhibits moredesirable properties and/or characteristics (e.g., low surface tensionfluid strikethrough time) when the second nonwoven component layer 232′is positioned closer to the skin of the wearer and the source of thefluid insult into the absorbent article (and prior to use, closer to thecentral longitudinal axis 59) than the fourth nonwoven component layer228′. The arrow 213 of FIG. 3A illustrates the direction of flow of abody exudates or fluid relative to the positioning of the variousnonwoven component layers.

In one embodiment, a web of material, such as the SMNS web 212′, mayhave the same or similar properties as the properties as that describedabove with regard to an SNS web 212. For example, the SMNS web 212′ mayhave a total basis weight of less than 30 gsm, alternatively, less than15 gsm, alternatively, e.g., 13 gsm, alternatively, less than 10 gsm,and alternatively, in the range of 7 gsm to 15 gsm. In such anembodiment, the web of material may not comprise a film and may have anair permeability of at least 1 m³/m²/min, alternatively, at least 10m³/m²/min, alternatively, at least 20 m³/m²/min, and alternatively, atleast 40 m³/m²/min but less than 100 m³/m²/min. In one embodiment, theweb of material may have a local basis weight variation of less than10%, alternatively, less than 8%, and alternatively, less than 6% and a32 mN/m low surface tension fluid strikethrough time of at least 19seconds, alternatively, at least 23 seconds, alternatively, at least 30seconds, alternatively, at least 35 seconds, alternatively, at least 40seconds, alternatively, at least 45 seconds, and alternatively, at least50 seconds.

In one embodiment, the webs described herein, such as the SNS web and/orthe SMNS web, for example, may exhibit the specified properties evenwithout comprising a hydrophobic material, such as a hydrophobic meltadditive or a hydrophobic surface coating, for example. Such featuresprovide the webs of the present disclosure significant cost-savingadvantages over related webs as adding hydrophobic materials leads toadditional manufacturing cost and complexity. The inclusion of theN-fiber layer within the webs allows the webs to maintain a desirablelow surface tension fluid strikethrough time and air permeabilitywithout any hydrophobic materials or films. Without intending to bebound by any particular theory, applicants believe that the N-fiberlayer reduces the pore size of the webs by filing in voids within thespunbond and meltblown layers. By creating webs with smaller pore sizeswhen compared to the pore sizes of related webs, the webs of the presentdisclosure may have higher capillary drag forces to fluid penetrationand, thereby, a longer low surface tension fluid strikethrough time,even without comprising a hydrophobic material or a film. Still, whenlooking at the structure of the SNS or the SMNS webs, the efficacy ofthe N-fiber layer in boosting the barrier performance of the web was notexpected.

As referenced above, some absorbent articles comprise hydrophilicsurfactants or materials on topsheets and/or central portions thereof,for example, and also may comprise hydrophobic materials on barriercuffs thereof. The hydrophilic surfactants or materials may be used todraw bodily fluids toward an absorbent core of an absorbent article,while the hydrophobic materials restrict the flow of bodily fluidsthrough the barrier cuffs. In some instances, the hydrophilicsurfactants or materials may naturally migrate toward other materialsprior to use of the absorbent articles. When the hydrophilic surfactantsor materials come into contact with the barrier cuffs formed of webs ofmaterials, they reduce the web's ability to hinder low surface tensionbodily fluid flow through the barrier cuffs. However, the applicantshave found that the webs provided herein, such as the SNS web and/or theSMNS web, for example, may reduce the degradation of barrier propertiesof the web after hydrophilic surfactant's or material's migration fromthe topsheet or other central portion of an absorbent article to thebarrier cuffs, owing perhaps to the fact that the webs of the presentdisclosure have higher surface areas and dilute the migratinghydrophilic surfactants when used as the barrier cuffs, or used as aportion of the barrier cuffs. In that, in one embodiment, no hydrophobicmaterial may be present on the barrier cuffs, the hydrophilicsurfactants or materials may not spread out fully on the barrier cuffsand, therefore, may not reduce the barrier cuff's ability to restrictthe flow of low surface tension bodily fluids therethrough.

In other embodiments, it may be desirable for the webs to comprise ahydrophobic melt additive and/or a hydrophobic surface coating. Thehydrophobic melt additive and/or the hydrophobic surface coating mayincrease the low surface tension fluid strikethrough time of the SNS weband/or the SMNS web, while not significantly decreasing the airpermeability. Hydrophobic additive formulations and methods forincorporating them in nonwoven webs are described by Catalan in USapplications publication Nos. 2006/0189956 filed on Feb. 18, 2005 and2005/0177123 filed on Feb. 10, 2005, and in U.S. application Ser. No.12/691,929 filed on Jan. 22, 2010, and U.S. application Ser. No.12/691,934 filed on Jan. 22, 2010 both to J J Tee et al. that are allassigned to The Procter and Gamble Company. Some suitable, but notlimiting, hydrophobic materials used as hydrophobic surface coatingsand/or hydrophobic melt additives may comprise one or more siliconepolymers that are also substantially free of aminosilicones. Suitablesilicone polymers are selected from the group of silicone MQ resins,polydimethysiloxanes, crosslinked silicones, silicone liquid elastomers,and combinations thereof. Typically, the molecular weight of suchsilicone polymers should be at least 4000 MW. However, the molecularweight of such silicone polymers may be at least 10,000 MW, at least15,000 MW, at least 20,000 MW, or at least 25,000 MW. Suitablepolydimethylsilosxanes are selected from the group consisting ofvinyl-terminated polydimethsiloxanes, methyl hydrogen dimethylsiloxanes,hydroxyl-terminated polydimethysiloxanes, organo-modifiedpolydimethylsiloxanes, and combinations thereof.

Alternatively, fluorinated polymers may also be used as the hydrophobicsurface coatings and/or the hydrophobic melt additives. Suitablefluorinated polymers are selected from the group of telomers andpolymers containing tetrafluoroethylene and/or perfluorinated alkylchains. For instance, fluorinated surfactants, which are commerciallyavailable from Dupont under the tradename Zonyl®, are suitable for useherein.

In one embodiment, these hydrophobic materials may be deposited onto thesurface of the SNS web and/or the SMNS web in amounts of from at least 1μg of coating per 1 g of a web. A suitable amount of silicone polymerpresent on the surface may be at least 100 μg/g. In certain embodiments,the amount of silicone polymer present on the surface may be at least200 μg/g. In other embodiments, the amount of silicone polymer presenton the surface may be at least 300 μg/g, alternatively, at least 400μg/g or, alternatively, in the range of 1000 μg/g to 10,000 μg/g, forexample.

The hydrophobic surface coating may be delivered to a substrate and/orfiber surface by any conventional methods. Without intending to be boundby any particular theory, it is believed that the hydrophobic surfacecoatings disclosed herein, when topically applied to the surface of afibrous substrate (e.g., nonwoven surface), tend to envelop or at leastpartially coat one or more fibers and/or fibrous structures of the webin such a way that a cohesive, uniform film-like network is formedaround the fiber and/or fibrous structures, and partially also fills thepore network of the web. In certain embodiments, hydrophobic materialsmay be included as an additive to a hot melt composition (e.g., blendedinto a thermoplastic melt), which is then formed into fibers and/or asubstrate (e.g., by spunbonding, meltblowing, or extruding) (referred toherein as “hydrophobic melt additives”). Those minute additions ofhydrophobic materials (chemical components) increase the contact angleof the fibers with liquid to some degree; namely for 1000 μg/g thecontact angle for water increases from 100 to 110 degrees.

In one embodiment, a web of material comprising a hydrophobic surfacecoating and/or a hydrophobic melt additive, such as an SNS web or anSMNS web comprising these materials, for example, may have a total basisweight of less than 30 gsm, alternatively, less than 15 gsm, e.g., 13gsm, alternatively, less than 10 gsm, and alternatively, in the range of7 gsm to 15 gsm. In such an embodiment, the web of material may notcomprise a film and may have an air permeability of at least 1m³/m²/min, alternatively, at least 10 m³/m²/min, alternatively, at least20 m³/m²/min, and alternatively, at least 40 m³/m²/min but less than 100m³/m²/min. In one embodiment, the web of material may have a local basisweight variation of less than 10%, alternatively, less than 8%, andalternatively, less than 6% and a 32 mN/m low surface tension fluidstrikethrough time of at least 30 seconds, alternatively, at least 35seconds, alternatively, at least 40 seconds, alternatively, at least 47seconds, alternatively, at least 50 seconds, alternatively, at least 55seconds, alternatively, at least 60 seconds, alternatively, at least 65seconds, and alternatively, at least 70 seconds.

In one embodiment, the webs of the present disclosure, for example, theSNS or the SMNS webs, and in the relevant comparisons, e.g., with SMS,all have a porosity (% void fraction) of over 80% (e.g., 85%). Theporosity of 85% arises since the M and N fiber layers have 80% to 85%porosity and the first nonwoven component layers 132 have 85% to 92%porosity. A lower porosity may be achieved by flat calendering andreducing the breathability or by referring to a film, e.g., amicroporous film, however the desired air permeabilities listed abovethen may become unachievable.

Mechanical Bonding

During construction of an absorbent article, such as absorbent article10, for example, a web, such as an SNS web and/or an SMNS web, forexample, may need to be attached to another component of the absorbentarticle 10. In some embodiments, as described in more detail below, afirst portion of the web may be mechanically bonded to a second portionof the web, thereby creating a hem, for example. The components of theabsorbent article sought to be mechanically bonded may be passed througha mechanical bonding apparatus.

FIG. 15 illustrates a simplified dynamic mechanical bonding apparatus320 in accordance with one non-limiting embodiment of the presentdisclosure. The mechanically bonding apparatus 320 may comprise apatterned cylinder 322, an anvil cylinder 324, an actuating system 326for adjustably biasing cylinders 322 and 324 towards each other with apredetermined pressure within a predetermined range of pressures, anddrivers 328 and 329 for rotating the cylinders 322 and 324,respectively, at independently controlled velocities to provide anoptional predetermined surface velocity differential therebetween. Inone embodiment, the cylinders 322 and 324 may be biased towards eachother at approximately 10,000 psi, for example.

A web 341, a web 342, and a laminate 345 are also shown in FIG. 15. Invarious embodiments, the web 341 may be various webs of nonwovenmaterial, such as a 13 gsm polypropylene SNS web and/or SMNS web, forexample, and the web 342 may be, for example, a 12 gsm, 1.5 denierpolypropylene spunbond topsheet, or other component of an absorbentarticle. Additionally, the apparatus 320 may comprise a frame, notshown, and drivers, not shown, for driving rolls 331 through 338 forcontrollably forwarding the web 341 and the web 342 through the nip 343defined between the patterned cylinder 322 and the anvil cylinder 324,and for enabling forwarding the resulting laminate (laminate 345) to adownstream apparatus, such as a roll winder or web converting apparatus:for example, a disposable diaper converter. As used herein, “laminate”refers to at least two components of an absorbent article sharing atleast one mechanical bond. Generally, the driving rolls 331 through 338,inclusive, may be provided for guiding and advancing the webs or the web341 and the web 342, and the laminate 345 through and away from nip the343. These rolls 331 through 338 may be driven at surface velocitieswhich maintain predetermined levels of tension or stretch so thatneither slack web conditions nor excessively tensioned/stretched websand/or laminate precipitate undesirable deleterious consequences.

For the purposes of clarity, neither the upstream ends or sources of theweb 341 and the web 342, nor the downstream destination or user of thelaminate 345 are shown. In some embodiments, the mechanically bondingapparatus 320 may received more than two laminates for bonding, and thelaminates to be mechanically bonded may comprise, for example,thermoplastic films, nonwoven materials, woven materials, and other websin roll form; and to provide upstream unwinding and splicing devices toenable forwarding continuous lengths of such laminate through themechanical bonding apparatus 320 and/or other converters to makeproducts comprising laminated and/or other web elements at controlledvelocities and under controlled tension. Furthermore, for simplicity andclarity, the mechanical bonding apparatus 320 is described herein ascomprising the cylinders 322 and 324. However, the cylinders 322 and 324are but one embodiment of nip defining members as stated. Accordingly,it is not intended to thereby limit the present disclosure to anapparatuses comprising cylinders. Similarly, the use of the term“pattern element” is not intended to limit the present disclosure tobonding patterns comprising only discrete, spaced pattern elements tothe exclusion of other patterns: e.g., reticulated patterns or patternscomprising continuous or elongate lines of bonding.

In one embodiment, the actuating system 326 for biasing the patternedcylinder 322 towards the anvil cylinder 324 may comprise a pressureregulator 355, and a pneumatic actuator 356, for example. The pressureregulator 355 may be adapted to have its inlet connected to a supplysource “P” of pressurized air, and to have its outlet connected to thepneumatic actuator 356 in order to adjust and control the pneumaticactuator means loading of the cylinders 322 and 324 towards each other.Although only one pneumatic actuator 356 is illustrated in FIG. 15,additional actuators may connected to each end journal of the patternedcylinder 322; and each end journal may be supported by frame members andancillary hardware (not shown) to be vertically moveable so that, infact, the pressure biasing mechanism may be effective.

In one embodiment, the drivers 328 and 329, are provided toindependently drive the cylinders 322 and 324, respectively. Thus, theymay rotate the cylinders 322 and 324 so that there is a predeterminedbut adjustable relationship between the surface velocities of thecylinders 322 and 324. In various embodiments, the rotation may besynchronous, or asynchronous: equal surface velocities; or with apredetermined surface velocity differential with either of the cylinders322 and 324 being driven faster than the other. In one embodiment thatis integrated into a disposable diaper converter, the patterned cylinder322 is driven by a converter line drive through a gear train so that itssurface velocity is essentially matched to the line velocity of theconverter; and, the anvil cylinder 324 is powered by an independentlyspeed controlled DC (direct current) drive. This implementation mayenable adjustment of the surface velocity of the anvil cylinder 324 tobe equal to, or less than, or greater than the surface velocity of thepatterned cylinder 322 by predetermined amounts or percentages.

Referring now to FIG. 16, the patterned cylinder 322 may be configuredto have a cylindrical surface 352, and a plurality of pins, nubs, orother protuberances, collectively referred to as pattern of elements351, which extend outwardly from the surface 352. As shown in FIG. 16,the patterned cylinder 322 may have a saw-tooth shape pattern ofelements 351, which may extend circumferentially about each end of thepatterned cylinder 322. Such a patterned cylinder 322 may be configured,for example, to laminate, lap-seam, or otherwise mechanically bondtogether the laminate 341 and the laminate 342. In one embodiment, thepatterned cylinder 322 may be comprised of steel and may have a diameterof 11.4 inches (about 29 cm.), for example. While the illustratedembodiment shows two sets of pattern of elements 351 extendingcircumferentially around the patterned cylinder 322, in otherembodiments, the patterned cylinder 322 may have more or less patternsof elements 351 and the overall width of the patterned cylinder 322 mayvary accordingly. The anvil cylinder 324 (FIG. 15) may be smoothsurfaced, right circular cylinder of steel. In one embodiment, the anvilcylinder 324 may have a 4.5 inch (about 11.4 cm.) diameter and may beindependently power rotated by a speed controlled direct current motor,for example, although the embodiments are not limited to suchconfigurations.

FIG. 17 is a plan view of a fragmentary portion of the laminate 345 ofFIG. 16 comprising overlapping edge portions of the laminate 341 and thelaminate 342 which have been mechanically bonded together by a patternof bond sites 351 b: the pattern being the pattern of pattern elementswhich extends circumferentially about one end of patterned cylinder 322.(FIG. 16). The bond sites 351 b (e.g., bond points, bond areas, dimples,nubs, land areas, cells, or elements) on the laminate 345 may have anysuitable geometric shape (e.g., triangle, square, rectangle, diamond,other polygonal shapes, circle, ellipse, oval, oblong, and/or anycombinations thereof). The shape and size of the bond pattern may beselected to yield bond sites 351 b having predetermined strength andelasticity characteristics in the MD and CD directions, generallyreferred to in the art as tensile and elongation physical properties.The bond sites' 351 b arrangement may be hexagonal, rectangular, square,or any other suitable polygonal shapes, for example. Generally,compressed fibers at the bond sites 351 b give strength andreinforcement to the laminate 345, such a barrier cuff nonwoven webcomprising an SNS web and/or SMNS web bonded to a spunbond topsheet ofan absorbent article, for example. For clarity, the MD oriented edges ofthe laminate 341 and the laminate 342 are designated as 341 e and 342 e,respectively, in FIG. 17.

As is to be appreciated, the pattern of elements 351 on the patternedcylinder 322 may be configured to generate a variety of bond sitepatterns. FIGS. 18A-D illustrate patterns of bond sites in accordancewith various non-limiting embodiments. In certain embodiments, thearrangement of the bond sites 351 b may be staggered to reduce oreliminate the stress concentration of a “straight” line in the MD. Thewidth (illustrated as “W”) of the pattern may vary. For example, incertain embodiments the width may be less than 10 mm, alternatively,less than 5 mm, alternatively, less than 4 mm, and, alternatively, lessthan 3 mm. Some patterns, for example, may comprise bond sites 351 bhaving different shapes and/or cross sectional areas. In one embodiment,individual bond sites 351 b may be 2 mm long and 1 mm wide, and, in oneembodiment, individual bond sites 351 b may be 4 mm long and 1 mm wide,although other bond site sizing may be used in other embodiments.Furthermore, the area of individual bond sites 351 b may vary. In oneembodiment the bond area may be 4 mm², alternatively, alternatively, 2mm², and, alternatively, 1.5 mm² or less. The bond density per square cmmay vary based on the particular application. For example, in oneembodiment, there may be 15 bonds per cm², alternatively, 10 bonds percm², and, alternatively, less than 10 bonds per cm². Based on the bonddensity, the relative bond area (which is the bond density multiplied bythe bond area per pin) may be 50% or less in some embodiments and,alternatively, may be 30% or less in other embodiments.

As the nonwoven web, such as the SNS web and the SMNS web, for example,is compressed during the mechanical bonding process, without intendingto be bound by any particular theory, it is believed that the rapidcompression of the materials beneath the protuberances 351 causes therespective materials to be rapidly deformed and at least partiallyexpressed from beneath the pattern of elements 351. As a result,structures of entangled or otherwise combined material are formedbeneath and/or around the protuberances to create mechanical bonds inthe nonwoven web. In various embodiments, the mechanical bonds may becreated without the use of adhesives, heat sources for a thermal weldingprocess, or an ultrasonic wave source.

FIG. 19 is a sectional view taken along line 19-19 of FIG. 17, whichillustratively shows a bond site 351 b which mechanically bonds the web341 and the web 342 together to form the laminate 345. In theillustrated embodiment, the web 341 may be an SNS web material, with anN-fiber layer 432 positioned intermediate a first nonwoven componentlayer 425 and a second nonwoven component layer 436. The web 342 maycomprise any suitable materials, such as a topsheet of an absorbentarticle, a spunbond or another SNS web, or a second portion of the web341, for example. In some embodiments, one or both of the web 341 andthe web 342 may comprise an SMNS web, comprising both a meltblown layerand a N-fiber layer, in addition to two spunbond layers. In someembodiments, at least one of the webs 341, 342 may comprise apolypropylene component. In one embodiment, if an SMNS web is passingthrough the mechanical bonding apparatus 320 (FIG. 15), the material maybe oriented such that the nubs (or pins) exert force on the N-fiberlayer before exerting force on the meltblown layer. This configurationmay lead to a displacement and more uniform expression of the N fibersinto the underlying and surrounding fibrous structure, with a resultinghigher bond strength than when the M layer (or generally coarser fiberlayer) are more proximate to the nubs.

As shown in FIG. 19, the bond site 351 b may have a bottom surface 351bb and a ring 376 formed substantially around the periphery of the bondside 351 b, defined as the grommet ring. The grommet ring 376 may extendabove the first nonwoven component layer 425 to form a ridge-likestructure generally surrounding each bond site 351 b. Without intendingto be bound by any particular theory, it is believed that thatcompression forces applied to the laminate 341 and the laminate 342during the mechanical bonding process cause material flow (e.g., fiberflow) from a bond center 378 toward the bond's periphery thereby formingthe grommet ring 376. In some embodiments, the thickness of the bondsite 351 b at the bond center 378 may be less than 50 micrometers and,alternatively, less than 15 micrometers. Despite the formation of arobust bond using the aforementioned techniques, the bond site 351 b mayand should still maintain a material barrier 380 across the entirebottom surface 351 bb. If the material barrier 380 across the bottomsurface 351 bb is breached, the laminate 345 may undesirably leakthrough the breach when a fluid is introduced to the bond site 351 b.

Compared to the bond site 351 b, in a thermal bond or a calender bondmost of the adhesive force comes from fusion of materials in the bondcenter, and formation of a grommet ring is may not occur. In fact, theaverage mass of material per unit area (i.e., basis weight) inside of athermal bond point is generally the same as in the unbonded surroundingarea. In contrast, the grommet ring 376, for example, is postulated toprovide most of the bond strength for the mechanical bond, and the bondcenter 378 has a significantly reduced basis weight compared to thesurrounding area. Furthermore, the use of the N-fiber layer(s) in thenonwoven webs helps to provide a significant increase in the uniformity.In some embodiments, the local basis weight variation may be less than15% , alternatively, less than 10%, and, alternatively, in the range of5% to 10%.

Without intending to be bound by any particular theory, with regard toperformance during the mechanical bonding process, applicants believethat the N-fibers (with diameters less than 1 micron) in the nonwovenweb significantly increase the surface area of the web by 4 to 5 times(inversely proportional to the diameters of the fibers that areproduced) compared to SMS or spunbond nonwoven webs of same basisweight. The increase in surface area may serve to increase the number offibers underneath the pattern of elements during the mechanical bondingprocess to better distribute the energy from the pattern of elements anddistribute it throughout the web. Additionally, the use of the N-fibersmay allow the web to be covered more densely to create a more uniformweb having a relatively low basis weight variation (e.g., less than 10%local basis weight variation). As a result, the materials incorporatingthe N-fibers display less defects within the bond sites. In someembodiments, mechanically bonded webs comprising at least one N-fiberlayer may have a defect occurrence rate of less than 0.9%, alternativelyless than 0.54% and, alternatively, less than 0.25%. with the bondednonwoven web having a basis weight (combined basis weight of two webs ormore) of less than 25 gsm. Furthermore, in accordance with theembodiments of the present disclosure, webs incorporating the N-fiberlayer, such as SNS webs and SMNS webs, for example, may utilizegenerally small bond areas as compared to other webs, such as SMS webs.Moreover, the desired performance of the webs may be achieved with lowerbasis weights and/or lower stock heights when the N-fiber layer is used.In some embodiments, the bonded nonwoven material may have a low basisweight (e.g., less than 25 gsm or less than 15 gsm) and achievemechanical bonds with suitable defect occurrence rates.

FIG. 20 is a sectional perspective view of the bond site 351 b shown inFIG. 19. As illustrated, the grommet ring 376 extends generally aroundthe periphery of the bond site 351 b. Additionally, the material barrier380, such as a membrane, extends across the bond site 351 b in order tosubstantially “seal” the bond to maintain the bond's fluid barriercharacteristics.

Utilizing the aforementioned mechanical bonding techniques, a barriercuff, for example, may be attached to, or otherwise integrated with, anabsorbent article. Referring to FIGS. 1, 2, 3A-3B and 5, the absorbentarticle 10 may comprise a pair of longitudinal barrier cuffs 51,attached to a chassis 47. The chassis 47 may be any component orportion, or collection of components or portions, of the absorbentarticle 10, such as the topsheet 20, for example. Each longitudinalbarrier cuff 51 may be comprised of a web 65, such as an SNS web or anSMNS web, having the characteristics described above. For example, theweb 65 may comprise a first nonwoven component layer 125 comprisingfibers having an average diameter in the range of 8 microns to 30microns and a second nonwoven component layer 132 comprising fibershaving an average diameter of less than 1 micron. The web of material 65of the longitudinal barrier cuffs 51 may have a local basis weightvariation less than 10%, alternatively, less than 8%, or alternatively,less than 6%. In fact, applicants estimated that a low defect rate ofless than 10 bond defects per 5 m of a 25 gsm laminate (bond occurrencerate less than 0.35%) would require an SMS web to have an even lowerlocal basis weight variation of 3% or less. In one embodiment, an SNS orSMNS web of 13 gsm (comprising an N and M layer of 1 gsm each) or less,when combined with a spunbond layer of 12 gsm or less is sufficient torequire a local basis weight variation of 6% or less in order to achievea defect rate of less than 10 bond defects per 5 m of laminate (bondoccurrence rate less than 0.35%). The variation of 10% would suffice foran SNS or SMNS web of 13 to 15 gsm with the N layer of 1.5 gsm to 3 gsm,or combining two layers of SNS or SMNS webs of 12 gsm to 13 gsm each.Each of the longitudinal barrier cuffs 51 may comprise a longitudinalzone of attachment 49 where the longitudinal barrier cuff 51 attaches tothe chassis 47. In some embodiments, the longitudinal zone of attachment49 may extend generally parallel to the central longitudinal axis 59(FIG. 1). In some embodiments, the zone of attachment 49 may begenerally linear or may be curved, or a combination. Furthermore, thezone of attachment 49 may be substantially continuous along theabsorbent article or, alternatively, discontinuous. Furthermore, eachlongitudinal barrier cuffs 51 may have a longitudinal free edge 64 and aplurality of mechanical bonds 68 disposed between the zone of attachment49 and the free edge 64. In one embodiment, the plurality of mechanicalbonds 68 forms a hem proximate to the longitudinal free edge 64. Forexample, the plurality of mechanical bonds 68 may attach, for example, afirst portion of the web material 59 to a second portion 61 of the web65, which may be referred to as a hem fold bond. In some embodiments,the mechanical bonds 68 may attach the web 65 to a portion of theabsorbent article 10. The mechanical bonds 68 may be similar to the bondsite 351 b illustrated in FIGS. 19-20, for example. The mechanical bonds68 may, for example, bond the topsheet 20 to the longitudinal barriercuffs 51. Furthermore, the mechanical bonds 68 may be disposed in anysuitable pattern or configuration, such as the patterns illustrated inFIGS. 18A-18D, for example.

In another embodiment, referring to FIG. 3B, longitudinal barrier cuffs51 of the absorbent article 10 may each comprises a first layer of theweb of material 65 a and a second layer of the web of material 65 b. Thefirst and second layers of web material 65 a and 65 b, may each comprisean SNS web or an SMNS web, for example. Furthermore, as illustrated, thelongitudinal barrier cuff 51 may be folded in order to form to twolayers of web material 65 a and 65 b. In other embodiments, two separatewebs of material 65 a and 65 b may be joined, bonded, or otherwiseattached to form the longitudinal barrier cuff 51. The longitudinalbarrier cuffs 51 may comprise a longitudinal zone of attachment 49 wherethe longitudinal barrier cuff attaches to the chassis 47 and alongitudinal free edge 64. A plurality of mechanical bonds 68 may attachthe first and second layers of the web of material 65 a and 65 b. Insome embodiments, the plurality of mechanical bonds 68 attach at leaston of the first and second layers of the web of material 65 a and 65 bto the chassis 47. In one embodiment, the plurality of mechanical bonds68 have a defect occurrence rate of less than 0.9%, alternatively, lessthan 0.5% and, alternatively, less than 0.25%. In some embodiments, theplurality of mechanical bonds 68 may be disposed along, or generallyproximate to, the longitudinal zone of attachment 49.

In one embodiment, the SNS web and/or the SMNS web may comprise, or maycomprise a portion of, a component of an absorbent article other than alongitudinal barrier cuff, such as a backsheet of a diaper, for example,owing to the webs' superior properties of air permeability, low surfacetension fluid strikethrough time, basis weight, and local basis weightvariation. Likewise, the SNS web and/or the SMNS web may also be used tocomprise any other suitable portions of various consumer absorbentarticles or other suitable non-absorbent articles or portions thereof.Some non-limiting examples of non-absorbent articles that may be formedof, or formed partially of, the SNS web and/or the SMNS web are consumerdisposable water filtration components, air freshener components usingperfume release for odor elimination, and surfactant release componentsin detergents and detergent capsules.

In other embodiments, the SNS web and/or the SMNS web may be formedwith, attached to, and/or used with a film, such as microporous ormicro-apertured films (or films with risk of pin holes), for example, toincrease the low surface tension fluid strikethrough times of the websfor desired applications, such as when used as a backsheet of a diaper,for example. In still other embodiments, the SNS web and/or the SMNS webmay comprise or be coated with a hydrophobic melt additive and/or ahydrophobic surface coating to again increase the low surface tensionfluid strikethrough times of the webs for desired applications. In oneembodiment, the SNS web and/or the SMNS web may comprise both a film anda hydrophobic melt additive and/or a hydrophobic surface coating, forexample. Such web embodiments with the film, the hydrophobic meltadditive, and/or the hydrophobic surface coating may comprise or may beused as components of any suitable absorbent or non-absorbent articles,such as diaper backsheets, catamenial pad topsheets or backsheets, forexample.

Tests Air Permeability Test

The air permeability is determined by measuring the flow rate ofstandard conditioned air through a test specimen driven by a specifiedpressure drop. This test is particularly suited to materials havingrelatively high permeability to gases, such as nonwovens, aperturedfilms and the like.

A TexTest FX3300 instrument or equivalent is used. (Available by TextestAG in Switzerland (www.textest.ch), or from Advanced Testing InstrumentsATI in Spartanburg S.C., USA.) The Test Method conforms to ASTM D737.The test is operated in a laboratory environment at 23±2° C. and 50±5%relative humidity. In this test, the instrument creates a constantdifferential pressure across the specimen which forces air through thespecimen. The rate of air flow through the specimen is measured inm³/m²/min, which is actually a velocity in m/min, and recorded to threesignificant digits. The test pressure drop is set to 125 Pascal and the5 cm² area test head is used. After getting the system operational, the1 cm² insert is installed (also available from Textest or from ATI). Thesample of interest is prepared and specimens cut out to to fit into the1 cm² head insert. After malting the measurement of a specimen accordingto operating procedure, the result is recorded to three significantdigits accounting for the area difference between the 1 cm² test areainsert and the 5 cm² head. If the FX3300 instrument is not accountingfor this automatically, then each specimen's result is manuallyrecalculated to reflect the actual air permeability by accounting forthe area difference between the 1 cm² test area insert and the 5 cm²head. The average of 10 specimens' air permeability data of this sampleis calculated and reported.

Surface Tension of a Liquid

The surface tension of a liquid is determined by measuring the forceexerted on a platinum Wilhelmy plate at the air-liquid interface. AKruss tensionmeter K11 or equivalent is used. (Available by Kruss USA(www.kruss.de)). The test is operated in a laboratory environment at23±2° C. and 50±5% relative humidity. The test liquid is placed into thecontainer given by the manufacturer and the surface tension is recordedby the instrument and its software.

Surface Tension of a Fiber Basis Weight Test

A 9.00 cm2 large piece of web, i.e. 1.0 cm wide by 9.0 cm long, is cutout of the product, and it needs to be dry and free from other materialslike glue or dust. Samples are conditioned at 23° Celsius (±2° C.) andat a relative humidity of about 50% (±5%) for 2 hours to reachequilibrium. The weight of the cut web pieces is measured on a scalewith accuracy to 0.0001 g. The resulting mass is divided by the specimenarea to give a result in g/m² (gsm). Repeat for at least 20 specimensfor a particular sample from 20 identical products. If the product andcomponent is large enough, more than one specimen can be obtained fromeach product. An example of a sample is the left diaper cuff in a bag ofdiapers, and 10 identical diapers are used to cut out two 9.00 cm² largespecimens of cuff web from the left side of each diaper for a total of20 specimens of “left-side cuff nonwoven.” If the local basis weightvariation test is done, those same samples and data are used forcalculating and reporting the average basis weight.

Mechanical Bond Defect Occurrence Rate Test

The defect occurrence rate of a mechanical bonding pattern is determinedby determining the percentage of defective bonds in 5.0 meters of bondedmaterial. Defects are holes or skips or tears. Holes are defined as anarea of at least 0.39 mm² that is apertured or missing fromfrom thefilm-like membrane formed at the bond site material Skips are defined asan area of at least 1.00 mm² where the intended mechanical bond sitedoes not visually show a film-like membrane. The third type of defect, atear, is the result of a broken perimeter of the membrane where at least1.0 mm of the membrane's perimeter is torn or broken. See FIG. 20 forillustration of an example material barrier 380 (or “membrane”) within amechanical bond grommet. FIG. 21 illustrates what constitutes a goodmechanical bond, a bad, but not defective mechanical bond, and adefective mechanical bond during a Mechanical Bond

Defect Occurrence Rate Test.

A visual procedure is used to measure the defect occurrence rate from aproduced web of two or more webs, or from a web that is cut out of aproduct or product feature. First, take 5 m of the nonwoven web orequivalent number of products (e.g., 10 consecutive diapers of 0.5 m padcuff length) and inspect one side (e.g., the left longitudinal side orthe right longitudinal side of the diaper of the bond sites on thenonwoven webs for defects. Care is taken not to disrupt and damage thebonds and to select the section where the mechanical bonds have not beenoverbonded with a mechanical bond a second time or more.

If the component with the bonds of interest cannot be removed by simplycutting without disrupting and damaging the bonds, another method fordisintegration may be used, such as use of a THF bath to dissolve theadhesives. After carefully cutting out the component with the bonds ofinterest, label the specimens for tracking and later analysis.

Each mechanical bond pattern has a certain repeat length. The totaltarget number of bonds in the 5 m laminate web is obtained bymultiplying the 5 m length (5000 mm) with the number of bonds per repeatlength (#bonds/mm). If the mechanical bonds of the bond pattern ofinterest are so large as to extend the whole diaper length, the diaperlength is defined as repeat length. Cut out an extra (per example18^(th)) section according to above from the sample of interest, tapeits ends to a flat surface so the section is fully extended (manuallyextended to full length with reasonable force without damaging the weband to remove winkles and extend any elastomeric contraction) then slidea thin black piece of cardboard under the taped sample. Find a repeatlength of the bond pattern over at least a 100 mm section, which meansfor repeat lengths less than 100 mm long, that multiple individualrepeat lengths are selected. For example the bond pattern of FIG. 18A,when measuring the length from the top to the bottom of the shownpattern and it gives 200 mm, then the repeat length of the pattern inFIG. 18A is from the top edge of the C-shaped bond on the very top, tothe top edge of the third C-shaped bond from the top, and in thisexample would give 142 mm. All the bonds, even if of multiple shapes,are counted and added up in this overall repeat length. In the exampleof 18A, the overall repeat length is 142 mm, from top of first C-shapedbond to top of third. The number of bonds in this 142 mm repeat lengthis 16 bonds. The total number of bonds within the 5000 mm length is thus5000 mm multiplied by 16 bonds divided by 142 mm, which is 563 bonds.

Each bond site is examined under a microscope at 25× magnification. Thelens is used in conjunction with a the respective defect determinationtemplates; i.e. for holes template with a 0.39 mm² large circle(0.705+/−0.005 mm diameter), for skips the template with a 1.00 mm²large circle (mm diameter), and for tears the template with a 1.0 mmdiameter circle, which can be seen on the specimen when viewed throughthe eyepiece. See illustration in FIG. 21B, and outlined here furtherfor a hole defect. If the circle can fit within the hole, then the holeis counted as a hole defect. (see FIG. 21B) After one bond site isinspected, the next consecutive bond to be inspected is in thelengthwise direction of the diaper.

Holes are classified as H1, H2, . . . or H5, with the number reflectingthe number of consecutive mechanical bonds with a hole. Consecutivedefects in the same row in the diaper length direction are counted as asingle defect, i.e., five consecutive holes are counted as one H5defect. Record the results of the analysis in a data table like below,where for each specimen and each image the number of holes and skips isrecorded.

Defects per Image H1 H2 H3 H4 H5 S1 S2 S3 S4 S5 T1 T2 T3 T4 T5 specimenSpec 1 - image 1 S1-i2 Etc.

If there are more bond shapes not yet analyzed for holes, repeat thisstep for those and determine the number of its defects like above usingthis bond shape's hole defect limit.

Skip failures are classified with the respective template and recorded.as S1, S2, . . . , or S5, with the number reflecting the number ofconsecutive missing mechanical bonds. Consecutive defects in the samerow in the diaper length direction are counted as a single defect, i.e.,5 consecutive skips is counted as one S5 defect. Tear failures areclassified with the respective template and recorded. as T1, T2 . . . orT5 with the number reflecting the number of consecutive missingmechanical bonds. Consecutive defects in the same row in the diaperlength direction are counted as a single defect i.e. five consecutivetears are counted as one T5 defect. The total number of defects of allholes, skips and tears are added up to obtain the number of defects per5.0 m of web. Dividing this by the theoretical number of mechanicalbonds (mechanical bond density in number of mechanical bonds/cm timesthe length of the laminate (500 cm)) and multiplied by 100% yields thedefect occurrence rate in %. The theoretical number includes allmechanical bonds that would be on the 5 m laminate regardless of whethermaterial is properly bonded or not.

See FIGS. 21A, 21B, and 33A to 33G for illustration of identifying thedefects with this test.

Fiber Diameter and Denier Test

The diameter of fibers in a sample of a web is determined by using aScanning Electron Microscope (SEM) and image analysis software. Amagnification of 500 to 10,000 times is chosen such that the fibers aresuitably enlarged for measurement. The samples are sputtered with goldor a palladium compound to avoid electric charging and vibrations of thefibers in the electron beam. A manual procedure for determining thefiber diameters is used. Using a mouse and a cursor tool, the edge of arandomly selected fiber is sought and then measured across its width(i.e., perpendicular to fiber direction at that point) to the other edgeof the fiber. A scaled and calibrated image analysis tool provides thescaling to get actual reading in micrometers (μm). Several fibers arethus randomly selected across the sample of the web using the SEM. Atleast two specimens from the web (or web inside a product) are cut andtested in this manner. Altogether at least 100 such measurements aremade and then all data are recorded for statistic analysis. The recordeddata are used to calculate average (mean) of the fiber diameters,standard deviation of the fiber diameters, and median of the fiberdiameters. Another useful statistic is the calculation of the amount ofthe population of fibers that is below a certain upper limit. Todetermine this statistic, the software is programmed to count how manyresults of the fiber diameters are below an upper limit and that count(divided by total number of data and multiplied by 100%) is reported inpercent as percent below the upper limit, such as percent below 1micrometer diameter or %-submicron, for example.

If the results are to be reported in denier, then the followingcalculations are made.

Fiber Diameter in denier=Cross-sectional area (in m²)*density (inkg/m³)*9000 m*1000 g/kg.

The cross-sectional area is π*diameter²/4. The density forpolypropylene, for example, may be taken as 910 kg/m³.

Given the fiber diameter in denier, the physical circular fiber diameterin meters (or micrometers) is calculated from these relationships andvice versa. We denote the measured diameter (in microns) of anindividual circular fiber as d_(i).

In case the fibers have non-circular cross-sections, the measurement ofthe fiber diameter is determined as and set equal to the hydraulicdiameter which is four times the cross-sectional area of the fiberdivided by the perimeter of the cross of the fiber (outer perimeter incase of hollow fibers).

Fiber Diameter Calculations

The number-average diameter, alternatively average diameter,

$d_{num} = \frac{\sum\limits_{i = 1}^{n}d_{i}}{n}$

The mass-average diameter is calculated as follows:

mass average diameter,

$d_{mass} = {\frac{\sum\limits_{i = 1}^{n}\left( {m_{i} \cdot d_{i}} \right)}{\sum\limits_{i = 1}^{n}m_{i}} = {\frac{\sum\limits_{i = 1}^{n}\left( {\rho \cdot V_{i} \cdot d_{i}}\; \right)}{\sum\limits_{i = 1}^{n}\left( {\rho \cdot V_{i}} \right)} = {\frac{\sum\limits_{i = 1}^{n}\left( {\rho \cdot \frac{\pi \; {d_{i}^{2} \cdot {\partial x}}}{4} \cdot d_{i}} \right)}{\sum\limits_{i = 1}^{n}\left( {\rho \cdot \frac{\pi \; {d_{i}^{2} \cdot {\partial x}}}{4}} \right)} = \frac{\sum\limits_{i = 1}^{n}d_{i}^{3}}{\sum\limits_{i = 1}^{n}d_{i}^{2}}}}}$

where

fibers in the sample are assumed to be circular/cylindrical,

d_(i)=measured diameter of the i^(th) fiber in the sample,

∂x=infinitesimal longitudinal section of fiber where its diameter ismeasured, same for all the fibers in the sample,

m_(i)=mass of the i^(th) fiber in the sample,

n=number of fibers whose diameter is measured in the sample

ρ=density of fibers in the sample, same for all the fibers in the sample

V_(i)=volume of the i^(th) fiber in the sample.

${{The}\mspace{14mu} {polydispersity}\mspace{14mu} {of}\mspace{14mu} {fiber}\mspace{14mu} {diameter}\mspace{14mu} {distribution}} = \frac{\left( {{mass}\mspace{14mu} {average}\mspace{14mu} {fiber}\mspace{14mu} {diameter}} \right)}{\left( {{number}\mspace{14mu} {average}\mspace{14mu} {fiber}\mspace{14mu} {diameter}} \right)}$

Low Surface Tension Fluid Strikethrough Time Test

The low surface tension fluid strikethrough time test is used todetermine the amount of time it takes a specified quantity of a lowsurface tension fluid, discharged at a prescribed rate, to fullypenetrate a sample of a web (and other comparable barrier materials)which is placed on a reference absorbent pad. As a default, this is alsocalled the 32 mN/m Low Surface Tension Fluid Strikethrough Test becauseof the surface tension of the test fluid and each test is done on twolayers of the nonwoven sample simply laid on top of each other.

For this test, the reference absorbent pad is 5 plies of Ahlstrom grade989 filter paper (10 cm×10 cm) and the test fluid is a 32 mN/m lowsurface tension fluid.

Scope

This test is designed to characterize the low surface tension fluidstrikethrough performance (in seconds) of webs intended to provide abarrier to low surface tension fluids, such as runny BM, for example.

Equipment

Lister Strikethrough Tester: The instrumentation is like described inEDANA ERT 153.0-02 section 6 with the following exception: thestrike-through plate has a star-shaped orifice of 3 slots angled at 60degrees with the narrow slots having a 10.0 mm length and a 1.2 mm slotwidth. This equipment is available from Lenzing Instruments (Austria)and from W. Fritz Metzger Corp (USA). The unit needs to be set up suchthat it does not time out after 100 seconds.

Reference Absorbent Pad: Ahlstrom Grade 989 filter paper, in 10 cm×10 cmareas, is used. The average strikethrough time is 3.3±0.5 seconds for 5plies of filter paper using the 32 mN/m test fluid and without the websample. The filter paper may be purchased from Empirical ManufacturingCompany, Inc. (EMC) 7616 Reinhold Drive Cincinnati, Ohio 45237.

Test Fluid: The 32 mN/m surface tension fluid is prepared with distilledwater and 0.42+/−0.001 g/liter Triton-X 100. All fluids are kept atambient conditions.

Electrode-Rinsing Liquid: 0.9% sodium chloride (CAS 7647-14-5) aqueoussolution (9 g NaCl per 1 L of distilled water) is used.

Test Procedure

Ensure that the surface tension is 32 mN/m+/−1 mN/m. Otherwise remakethe test fluid.

Prepare the 0.9% NaCl aqueous electrode rinsing liquid.

Ensure that the strikethrough target (3.3+/−0.5 seconds) for theReference Absorbent Pad is met by testing 5 plies with the 32 mN/m testfluid as follows:

Neatly stack 5 plies of the Reference Absorbent Pad onto the base plateof the strikethrough tester.

Place the strikethrough plate over the 5 plies and ensure that thecenter of the plate is over the center of the paper. Center thisassembly under the dispensing funnel.

Ensure that the upper assembly of the strikethrough tester is lowered tothe pre-set stop point.

Ensure that the electrodes are connected to the timer.

Turn the strikethrough tester “on” and zero the timer.

Using the 5 mL fixed volume pipette and tip, dispense 5 mL of the 32mN/m test fluid into the funnel.

Open the magnetic valve of the funnel (by depressing a button on theunit, for example) to discharge the 5 mL of test fluid. The initial flowof the fluid will complete the electrical circuit and start the timer.The timer will stop when the fluid has penetrated into the ReferenceAbsorbent Pad and fallen below the level of the electrodes in thestrikethrough plate.

Record the time indicated on the electronic timer.

Remove the test assembly and discard the used Reference Absorbent Pad.Rinse the electrodes with the 0.9% NaCl aqueous solution to “prime” themfor the next test. Dry the depression above the electrodes and the backof the strikethrough plate, as well as wipe off the dispenser exitorifice and the bottom plate or table surface upon which the filterpaper is laid.

Repeat this test procedure for a minimum of 3 replicates to ensure thestrikethrough target of the Reference Absorbent Pad is met. If thetarget is not met, the Reference Absorbent Pad may be out of spec andshould not be used.

After the Reference Absorbent Pad performance has been verified,nonwoven web samples may be tested.

Cut the required number of nonwoven web specimens. For web sampled off aroll, cut the samples into 10 cm by 10 cm sized square specimens. Forweb sampled off of a product, cut the samples into 15 by 15 mm squarespecimens. The fluid flows onto the nonwoven web specimen from thestrike through plate. Touch the nonwoven web specimen only at the edge.

Neatly stack 5 plies of the Reference Absorbent Pad onto the base plateof the strikethrough tester.

Place the nonwoven web specimen on top of the 5 plies of filter paper.Two plies of the nonwoven web specimen are used in this test method. Ifthe nonwoven web sample is sided (i.e., has a different layerconfiguration based on which side is facing in a particular direction),the side facing the wearer (for an absorbent product) faces upwards inthe test.

Place the strikethrough plate over the nonwoven web specimen and ensurethat the center of the strikethrough plate is over the center of thenonwoven web specimen. Center this assembly under the dispensing funnel.

Ensure that the upper assembly of the strikethrough tester is lowered tothe pre-set stop point.

Ensure that the electrodes are connected to the timer. Turn thestrikethrough tester “on” and zero the timer.

Run as described above.

Repeat this procedure for the required number of nonwoven web specimens.A minimum of 5 specimens of each different nonwoven web sample isrequired. The average value is the 32 mN/m low surface tensionstrikethrough time in seconds.

35 mN/m Low Surface Tension Fluid Strikethrough Test

This test is done as described above with two exceptions. First, thetesting is done with one layer of the nonwoven web sample. Second, thetest fluid has a surface tension of 35 mN/m. The test fluid is createdby mixing 2 parts of the 32 mN/m fluid and 5 parts of deionized water.Before testing, the actual surface tension of the fluid needs to bechecked to ensure that it is 35+/−1 mN/m. If this fluid is not 35+/−1mN/m, it should be discarded and another fluid should be prepared.

Local Basis Weight Variation Test Purpose

The local basis weight variation test is intended to measure variabilityof mass distribution of 9 cm² areas throughout a lot of a nonwoven web.The local basis weight variation parameter describes a lack of desirableuniformity through a nonwoven web. Lower local basis weight variation isdesirable since it helps in consistency of most other qualities, such asbarrier properties, strength, and bonding, for example.

Principle

The mass of 1 cm by 9 cm area nonwoven web samples are measured andanalyzed to determine the local basis weight variation (i.e., massdistribution) throughout a lot of a web production. All individual dataof the lot, or of a portion of the lot, of interest is analyzed asstandard deviation and average and then the quotient is taken to providethe local basis weight variation. Stated another way, this gives arelative standard deviation (RSD) or coefficient of variation (COV) ofthe small area basis weight distribution.

The size of 1 cm by 9 cm for each replicate was selected such that themass of each replicate may be measured with sufficient digits andaccuracy on the specified scale.

Mass is measured in grams.

Grammage and basis weight are synonymous and are measured in g/m² (alsowritten gsm) units.

Samples of the nonwoven web are taken in the machine direction (the webneeds to be at least 1 cm wide such that it may be cut into specimens).

Equipment

Scale with a 0.0001 g sensitivity (alternatively, a scale with 0.00001 gsensitivity or with accuracy to within 0.1% of a target basis weight)(e.g., 13 gsm in 1 cm by 9 cm area weighs 0.0117 g; 0.1% of this mass is0.00001 g)

Die with 1.0 cm by 9.0 cm or 9 cm² area rectangular cut area optionallywith soft foam for easier sample removal. The die areas need to bewithin about 0.05 mm side length.

Hydraulic press: The hydraulic press is used to stamp out the nonwovenweb samples with the die.

Test Procedure Sampling:

At least 40 data points are needed to assess the local basis weightvariation of a defined nonwoven web sample. These data points are to besampled evenly throughout the nonwoven web sample.

Test specimens should be free of wrinkles and free from contaminantssuch as dust or glue.

Conditioning:

Use only clean and dry nonwoven web samples, at normal lab conditions(50+/−5% relative humidity and 23+/−2 degrees C.).

Procedure:

Cut out the replicate with the prepared die 9 cm² and the hydraulicpress. One layer is cut out. Paper may be put between the cutting boardand the sample for easier removal after cutting.

Be sure that the scale reads exactly zero (0.0000 g), or tare the scaleto 0.0000 g.

Measure the cut out replicate on the scale to the nearest 0.0001 g(alternatively, to the nearest 0.00001 g).

Record the lot, nonwoven web sample, replicate and result.

Continue the above steps for all selected replicates.

When the analysis is done for absorbent articles (e.g., diapers) thenidentical products are used, preferably consecutive diapers are testedwithin one bag, package, or case. Either the right of the left legbarrier cuff may be selected for the samples. For purposes of thisdescription, we assume that the right leg barrier cuff has beenselected.

Carefully cut the leg barrier cuffs out of the absorbent articles andnumber the cuffs sequentially (e.g., right leg barrier cuff of absorbentarticle 1). Proceed with doing the same for the remaining absorbentarticles in the bag, package or case.

Beginning with the cut out leg barrier cuff from absorbent article 1,fasten (e.g., tape) the leg barrier cuff to a piece of cardboard orplastic sheeting and put the die with the cut area (1 cm by 9 cm) ontothe barrier cuff and cut out a specimen. If there is still enough samplelength left, repeat this procedure one or two more times for two orthree more specimens out of the barrier cuff.

Weigh the cut out parts to the nearest 0.0001 g and record the result.

Proceed with the other cut out right side leg barrier cuffs from theother absorbent articles and measure the mass of the die cut 1 cm by 9cm sized pieces and record the data.

Repeat this procedure for as many absorbent articles as needed and, ifnecessary, several bags of absorbent articles, until the right sidebarrier cuff of the absorbent articles is characterized with 40 datapoints. Since a package of absorbent articles typically holds overtwenty absorbent articles, it is possible to cut out and measure 40 ormore replicates per side (in this case the right side) for each samplepackage of absorbent articles.

Repeat the whole procedure for the other side of the product (in thiscase the left side). The local basis weight variation should becalculated for each side.

Calculations

Calculate the average weight of the nonwoven web sample (40 individualreplicates)

Calculate the standard deviation of the nonwoven web sample

Calculate the Local Basis Weight Variation (standard deviation/averageweight).

Reporting

Report the local basis weight variability to the nearest first decimalpoint 0.1%, e.g., 7.329% becomes 7.3%.

Surface Tension Measurement of Fluid

The measurement is done with a video-based optical contact anglemeasuring device, OCA 20, by DataPhysics Instrument GmbH, or equivalent.Choose a clean glass syringe and dosing needle (with 1.65˜3.05 mm size)before filling the syringe with liquid to test; and then remove thebubble from the syringe/needle; adjust the position of the syringe,dosing needle and stage; a drop of the test liquid with known volumewill be formed at the lower end of the dosing needle. The detection ofthe drop shape is done by the software SCA20 and the surface tension iscalculated according to the Young-Laplace equation. The measurement iscarried out on an anti-vibration table in a closed hood.

The surface energy of fibers is also determined with this instrumentfollowing the Sessile Drop Technique.

Thickness or Caliper Test

The thickness test is done according to EDANA 30.5-99 normal procedurewith a foot of 15 mm diameter pushing down at 500 Pascal (i.e., a forceof 0.0884N). Start the test, wait for 5 seconds so the resultstabilizes, and record the result in millimeters to the nearest 0.01 mm.The sample analysis should include at least 20 measurements fromdifferent locations spread throughout the available sample.

Pore Size Distribution Test

The pore size distribution of nonwoven web samples is measured with theCapillary Flow Porometer, the APP 1500 AEXi from Porous Materials, Inc.or equivalent. The available pressure of the clean and dry air supplyshould be at least 100 psi so that pores down to 0.08 microns may bedetected. A nonwoven web sample is first cut and fully soaked in a lowsurface tension fluid, namely Galwick with a surface tension of 15.9mN/m. The nonwoven web sample size is 7 mm diameter. The soaked nonwovenweb sample is placed into the sample chamber of the instrument and thechamber is then sealed. Upon starting the automatic measurement cycle,gas flows into the sample chamber behind the nonwoven web sample andthen the gas pressure is slowly increased via the computer to a valuesufficient to overcome the capillary action of the fluid in the porehaving the largest diameter in the nonwoven web sample. This is thebubble point. The pressure inside the chamber is further increased insmall increments resulting in a flow of gas that is measured until allof the pores in the nonwoven web sample are empty of the low surfacetension fluid. The gas flow versus pressure data represents the “wetcurve.” When the curve continues to rise linearly, the sample isconsidered to be dry (i.e., the pores are emptied of the low surfacetension fluid). The pressure is then decreased in steps producing the“dry curve.” From the relationships of the “wet” and “dry” curves, thecomputer calculates the pore parameters including the mean-flow porediameter and a histogram of pore diameters across the tested range(e.g., from the bubble point down to about 0.08 microns or even lesswith higher gas pressure) as is known to those of skill in the porousmedia field.

Some key parameters for the test procedure with the capillary flowporometer are the following: the test fluid is Galwick with 15.9 mN/msurface tension; the test area opening size is 7 mm; and the tortuosityparameter is set to 1. Other parameters of the instrument are set to maxflow: 100,000 cc/min, bubble flow 3 cc/min, F/PT parameter 1000, zerotime 2 s, v2incr 25 cts*3, preginc 25 cts*50, pulse delay 0 s, maxpres 1bar, pulsewidth 0.2 s, mineqtime 10 s, presslew 10 cts*3, flowslew 30cts*3, equiter 10*0.1 s, aveiter 10*0.1 s, max press diff 0.01 bar, maxflow diff 40 cc/min, starting press 0.1 bar, and starting flow 500cc/min.

Nonwoven Tensile Strength (in CD)

The nonwoven tensile strength (in CD) is measured using an Instron MTS3300 tensile tester, or equivalent according to WSP 110.4(05)B. Anonwoven web sample of 15 mm×50 mm, where the 50 mm length is along thelength of the diaper product. The sample width is 50 mm. The gaugelength is 5 mm, allowing for 5 mm to be placed in each sample clamp. Thetest speed is 100 mm/min. A stress-strain curve is measured until thesample breaks. The nonwoven tensile strength is defined as the maximumstress value observed of the curve.

Bond Peel Strength

The bond peel strength is defined as the force required to separate thetwo bonded layers of barrier leg cuff and the topsheet in thelongitudinal direction. The test is measured using an MTS 3300 tensiletester or equivalent. A nonwoven laminate specimen of 15 m×170 mm isremoved from the product. A free end is created in the last 20 mm bymanually peeling apart the topsheet from the barrier leg cuff layer,thus obtaining a free end with a cuff face and a topsheet face. The testspeed is 305 mm/min. The specimens are obtained from the product asdescribed in the Mechanical Bond defect occurrence rate test.

Procedure

Insert the free end of the barrier leg cuff layer of the specimen intothe lower jaw with the length axis of the sample perpendicular to theupper edge of the jaw, and close the jaw. Align the specimen between thelower and upper jaws. Insert the free end of the topsheet layer of thespecimen into the upper jaw with the length axis of the sampleperpendicular to the lower edge of the jaw and close the jaw with enoughtension to eliminate any slack, but less than 5 grams of force on theload cell. Do NOT zero the instrument after the specimen has beenloaded.

Start the tensile tester and data collection device simultaneously asdescribed by the manufacturer's instructions.

Remove the specimen from the clamps and return the crosshead to thestarting position in preparation for the next specimen.

If tearing has occurred during testing, cut another specimen from thesame general area of the sample. If tearing occurs during testing ofthis second specimen also, record the bond strength for the specimen as“total bond”.

Disregard results for the first 2.5 cm of peel. If the tensile tester iscomputer interfaced, set the program to calculate the average peel forcein grams for the specimen.

EXAMPLES Example 1

In this example, the second nonwoven component layer 132 comprisesN-fibers having fiber diameters (measured per the Fiber Diameter andDenier Test set forth herein), polydispersity, fiber diameter ranges(minimum-maximum measured), and amounts of submicron diameter fibers(less than 1 micron) illustrated in Table 1A below:

TABLE 1A Number Mass Fiber Amount of Average Average Standard DiameterSubmicron Diameter Diameter Polydispersity Deviation Range Fibers SampleNo. (microns) (microns) Ratio (microns) (microns) (%) N1 0.34 0.39 1.140.09 0.15-0.55 >99%   N2 0.33 0.45 1.36 0.09 0.08-0.78 >99%   N3 0.380.48 1.27 0.14 0.17-0.77 >99%   N4 0.68 0.73 1.08 0.14 0.40-0.98 >99%  N5 0.57 0.95 1.66 0.31 0.11-2.23 92% N6 0.84 0.96 1.13 0.22 0.25-1.5574% N7 0.85 1.02 1.19 0.27 0.26-1.60 79% N8 0.69 1.12 1.63 0.370.23-1.84 85% N9 1.03 1.21 1.18 0.33 0.28-1.98 43%  N10 0.78 1.23 1.590.39 0.29-2.31 80%

Comparative Example 1

A nonwoven component layer comprises meltblown fibers having fiberdiameters (measured per the Fiber Diameter and Denier Test set forthherein), polydispersity, fiber diameter ranges (minimum-maximummeasured), and amounts of submicron diameter fibers (less than 1 micron)illustrated in Table 1B below.

TABLE 1B Number Mass Fiber Amount of Average Average Standard DiameterSubmicron Sample Diameter Diameter Polydispersity Deviation Range FibersNo. (microns) (microns) Ratio (microns) (microns) (%) M1 0.69 1.64 2.390.58 0.15-2.68 80% M2 0.45 1.97 4.35 0.44 0.10-5.55 93% M3 0.61 2.994.91 0.65 0.07-8.44 86% M4 1.36 1.86 1.37 0.56 0.41-3.32 21% M5 1.782.15 1.21 0.55 0.84-3.99  4% M6 1.44 2.25 1.56 0.71 0.46-4.40 26% M71.71 2.62 1.54 0.82 0.70-4.76 10% M8 3.16 4.16 1.32 1.23 1.80-6.80  0%M9 1.85 4.10 2.22 1.39 0.67-6.44 23%  M10 1.54 4.60 2.99 1.47 0.20-8.1838%  M11 2.27 6.17 2.72 1.85  0.55-12.17 10%

In Table 1B, the samples identified by the numbers M1 through M3represent ultra-fine meltblown fibers, the samples identified by thenumbers M4 through M7 represent fine meltblown fibers, and the samplesidentified by the numbers M8 through M11 represent intermediatemeltblown fibers.

The data set forth in Table 1A and Table 1B is illustrated in FIGS. 22through 25. The number average diameter and the mass average diametervalues, shown in the Tables 1A and 1B, are depicted on the statisticallyfitted curves to the fiber diameter distributions in FIGS. 22 through25. FIG. 22 compares the fiber diameter distribution of the N-Fiberssample N1 with the fiber diameter distribution of the ultra-finemeltblown fibers sample M1. Similarly, FIG. 23 compares the fiberdiameter distribution of the N-Fibers samples N1 through N4 with thefiber diameter distribution of the ultra-fine meltblown fibers samplesM1 through M3. The comparison of N-Fibers and ultra-fine meltblownfibers shows that even though ultra-fine meltblown fibers samplescomprise significant number of fibers (at least 80%) with diameters lessthan 1 micron, they also comprise finite number of fibers (about 6% to20%) with diameters greater than 1 micron (to up to 8.4 microns), makingthe fiber distributions with long tails on the large diameter end. Thelong large diameter end tails of fiber distributions are well-describedby the mass average diameters, which range between 1.64 and 2.99 alongwith a polydispersity ratio ranging between 2.39 and 4.91. FIGS. 24 and25 compare the fiber diameter distributions of N-Fibers samples N1through N4 with the fine and intermediate size meltblown fiber samples,respectively. The meltblown fiber samples are labeled in FIGS. 24 and25. The fiber diameter distributions of the meltblown samples in FIGS.24 and 25, and Table 1B depict that fiber diameters range from submicron(<1 micron) to as large as 12 microns, making the fiber distributionsignificantly wide with long tails on the large fiber diameter end.Owing to the presence of large diameter fibers (illustrated by the longtails of the fiber distributions on the large fiber diameter end) in themeasured samples, listed in Table 1B, both the mass average and thenumber average diameters for all the measured meltblown samples lie onthe distribution tails, and the mass average diameters are more thanabout 1 standard deviation greater than the number average diameters. Incomparison, the N-fibers have a very small number of large diameterfibers in the measured samples. Therefore, the fiber diameterdistributions of N-Fibers have short tails, and both the number averageand the mass average diameters are tended towards the center of thefiber distributions, and are within about 1 standard deviation of thenumber average diameters.

Example 2A

In this example, various samples of nonwoven web materials A-i aretested. Their various properties are displayed in Table 2A. Samples G-iare embodiments of nonwoven web materials of the,present disclosure,while SMS samples A-F are provided merely for comparison purposes. Thelow surface tension fluid strikethrough times of the various samples areillustrated graphically in FIG. 26 (with the exception of sample J toprovide a graph with a better scale). As can be seen from FIG. 26, thelow surface tension fluid strikethrough times of samples G-I of thepresent disclosure are significantly higher than SMS samples A-F, evenwhen the SMS webs are coated with a hydrophobic coating (see SMS samplesD-F). The low surface tension fluid strikethrough values are determinedusing two plies of each sample and a 32 mN/m low surface tension fluid.

TABLE 2A Low Surface Total Basis Fine Fiber Tension Fluid Air SampleWeight Basis Weight Strikethrough Permeability No. Material Type (g/m²)(g/m²) (s) (m/min) A SMS 15.7 1 13 91 B SMS 16.9 3 16 72 C SMS 13.3 1.513 80 D SMS + Hydrophobic 15.2 1 19 96 Coating 1 E SMS + Hydrophobic17.1 3 20 84 Coating 1 F SMS + Hydrophobic 15.1 1 23 70 Coating 2 G SNS15.5 1.5 32 52 H SNS + Hydrophobic 15.6 1.5 47 50 Coating 1 I SMNS 13.31 (M) + 1 (N) 33 59

Example 2B

In this example, various samples of nonwoven web materials A-I (same asExample 2A) are tested. Their various properties are displayed in Table2B. Samples G-I are embodiments of nonwoven web materials of the presentdisclosure, while SMS samples A-F are provided merely for comparisonpurposes. The low surface tension fluid strikethrough times of thevarious samples are plotted against their number average diameter(microns) in FIG. 27. As is illustrated in FIG. 27, the low surfacetension fluid strikethrough time increases based on the smaller numberaverage diameter of the fibers in the sample. The low surface tensionfluid strikethrough values are determined using two plies of each sampleand a 32 mN/m low surface tension fluid.

TABLE 2B Sample ID A B D F G H I Material Type SMS SMS SMS SMS SNS SNSSMNS Hydrophobic Coating — — Type 1 Type 2 — Type 1 — Total Basis Weight(g/m²) 15.7 16.9 15.2 15.1 15.5 15.6 13.3 MeltBlown Fiber Basis 1 3 1 1— — 1 Weight (g/m²) N-Fiber Basis Weight (g/m²) — — — — 1.5 1.5 1Spunbond Number Average 14.85 15.57 15.95 18.40 16.98 16.98 15.61Diameter (micron) Spunbond Mass Average 15.03 15.71 16.10 18.47 16.9916.99 15.67 Diameter (micron) MeltBlown Number Average 1.96 1.85 2.202.69 — — 2.04 Diameter (micron) MeltBlown Mass Average 2.46 4.10 2.933.10 — — 3.72 Diameter (micron) Submicron M Fibers (%) 8% 23% 2% 0% — —  11% N-Fibers Number Average — — — — 0.49 0.49 0.35 Diameter (micron)N-Fibers Mass Average — — — — 0.54 0.54 0.43 Diameter (micron) SubmicronN Fibers (%) — — — — >99% >99% >99% Low Surface Tension Fluid 13 16 1923 32 47 33 Strikethrough (s) Air Permeability (m/min) 91 72 96 70 52 5059

Example 2C

In this example, the sidedness (i.e., which layer, the meltblown layeror the N-fiber layer, is positioned more proximal to the source of thelow surface tension fluid) of the SMNS nonwoven webs of the presentdisclosure is illustrated against the low surface tension fluidstrikethrough times of the SMNS webs. Referring to FIG. 28, in the dataset on the left, the meltblown layer (i.e., the fourth nonwovencomponent layer) was positioned more proximal to the low surface tensionfluid than the N-fiber layer in an SMNS web sample. In the data set onthe right, the N-fiber layer (i.e., the second nonwoven component layer)was positioned more proximal to the low surface tension fluid than themeltblown layer of the SMNS sample. As illustrated in FIG. 28, when theN-fiber layer is positioned closer to the source of the fluid, the SMNSweb provides a higher low surface tension fluid strikethrough time.

Turning to Table 2C below, a single layer of the SMNS web is testedusing the 35 mM/m Low Surface Tension Fluid Strikethrough Test.

TABLE 2C M facing liquid N facing liquid LSTST at 35 mN/m, Liquid → SMNSLiquid → SNMS 1 layer Average 202 230 StDev 69.1 76.8

The single layer SMNS web has a basis weight of 13 gsm (for morespecifics, see sample I in Example 2A and 2B). The variation in thisExample 2C is which side of the SMNS material is facing the source ofthe fluid (i.e., is the material positioned fluid-SMNS or fluid-SNMS).In the set of data on the left side of FIG. 28, the sample is positionedfluid-SMNS and in the data set on the right side of FIG. 28 ispositioned fluid-SNMS.

Statistical analysis shows that when the N-layer is positioned mostproximal to the low surface tension fluid source, a statisticallysignificant benefit of greater low surface tension fluid strikethroughtimes (with 89% certainty) is provided. Therefore, in one embodiment, anabsorbent article of the present disclosure, using the SMNS web as abarrier to fluid penetration, may have the N-layer of the SMNS webfacing inwards, towards the wearer of the absorbent article (i.e.,wearer-SNMS). This concept is illustrated in FIG. 3A, where the N-layerof the longitudinal barrier cuff 51 is positioned more proximal to thecentral longitudinal axis 59 than the than the M-layer.

Example 2D

In this example, a single layer of a nonwoven web is tested using the 35mN/m Low Surface Tension Fluid Strikethrough Test. Table 2D shows theresults of some comparative samples (SMS) and a sample of an SMNS web ofthe present disclosure.

TABLE 2D LSTST 1 layer at 35 mN/m Material (Average, s) 15 gsm SMS (1gsm M, 7 + 1 + 7 gsm total) (= sample A) 81.0 15 gsm SMS (3 gsm M, 6 +3 + 6 gsm total) (= sample B) 133.9 Hydrophobic surface coated 15 gsmSMS (1 gsm M; 311.7 additive is PDMS with surface energy 20 mN/m) (=sample D) SMNS* 13 gsm (5.5 + 1 + 1 + 5.5 gsm total) (= sample I) 229.6

The first sample in this table is equal to sample A of Example 2A and2B. The second sample is similar to sample B of Example 2A and 2B, buthas a lower overall basis weight (i.e., less spunbond basis weight) thefiber diameters of sample B's meltblown layer have a number averagediameter between 2 and 3 micrometers and a mass-average diameter ofabout 4 micrometers. The third sample in Table 2D is sample D fromExample 2A and 2B and is coated with a hydrophobic surface additiveaccording to Catalan in U.S. Pat. Publ. No. 2006/0189956 A1 in thefollowing manner: a 3% solution of a vinyl terminated PDMS (commerciallyavailable from Momentive as SM3200) and a methyl hydrogen PDMS(commercially available from Momentive as SM3010) is prepared and mixedfor 30 minutes. The SMS web is dipped into the solution and the exces'sliquid is squeezed out such that at least about 400 μg/g of the aqueoussilicone mixture is deposited on the SMS web. The SMS web is then driedin a convective oven at 120° C. for 1 minute and then cooled and storedin a dry and clean location until the SMS web is ready for testing. Theweight gain of the SMS web (i.e., the dry coating amount per squaremeter) needs to be less than 1%. The fourth sample in Table 2D is sampleI from Example 2A and 2B.

Referring to FIGS. 29 and 30, sample I shows a surprisingly largeadvantage in low surface tension fluid strikethrough times compared tothe SMS samples (the first three samples of Table 2D) and is more thanhalfway to the performance of a hydrophobic-coated SMS in this singlelayer 35 mN/m Low Surface Tension Fluid Strikethrough Test. The SMNSsample (sample I) has a lower total basis weight than any of the otherSMS samples (the first three samples of Table 2D), and does not have theadvantage of the PDMS coating which has a low surface energy of 20 mN/mto provide a higher contact angle. Sample I, even with having such a lowbasis weight and such a low fine fiber basis weight, and withouthydrophobic chemical modification, still is capable of producing veryhigh low surface tension fluid strikethrough times (e.g., above 150seconds or even above 200 seconds).

Example 3

In this example, pore size distribution of the SMS samples A and B fromExample 2A are compared with the SNS sample G and the SMNS sample I fromExample 2A. The pore size distribution of the embodiment of samples Gand I comprising N-fibers as the finest fiber layer is significantlydifferent and much narrower than the SMS samples A and B comprisingmeltblown fibers as the finest fiber layer, as illustrated in FIG. 31.The pore size distributions for all the samples have been statisticallyfitted with a mixture of constituent distributions (shown as dottedlines in the FIG. 31) corresponding to fine fiber and spunbond layers,with the largest pores corresponding to the spunbond layer because oflarger fiber diameters than the fine fibers. While the largest modecorresponds to the largest frequency of the thick spunbond fibers, thelowest mode corresponds to the largest frequency of the fine fibers, andthe intermediate mode (for the samples A, B, and I) corresponds to thelargest frequency of intermediate size fibers. The lowest mode value,mean flow, and bubble point pore diameters describing the pore sizedistribution are listed in Table 3 below for the samples A, B, G, and Ialong with their respective basis weights, fiber size distributions, lowsurface tension fluid strikethrough times, and air permeability values.The percent flow blocked by the lowest mode diameter is calculated fromintersection of the “wet flow” and “dry flow” curves (set forth in thePore Size Distribution Test) at the pressure corresponding to the lowestmode diameter. Table 3 also shows that the mean flow pore diametercorrelates with the mass-average diameter. Additionally, the low surfacetension fluid strikethrough time and air permeability correlate with themean flow and the lowest mode pore diameters. Clearly, samples G and Iof the present disclosure have significantly smaller pores andsignificantly longer low surface tension fluid strikethrough times whencompared to SMS samples A and B.

TABLE 3 Sample ID A B G I Material Type SMS SMS SNS SMNS Total BasisWeight 15.7 16.9 15.5 13.3 (g/m²) MeltBlown Fiber Basis 1 3 — 1 Weight(g/m²) N-Fiber Basis Weight — — 1.5 1 (g/m²) MeltBlown Number- 1.96 1.85— 2.04 Average Diameter (microns) MeltBlown Mass- 2.46 4.10 — 3.72Average Diameter (microns) Submicron M Fibers (%) 8% 23%  —  11%N-Fibers Number- — — 0.49 0.35 Average Diameter (microns) N-FibersMass-Average — — 0.54 0.43 Diameter (microns) Submicron N Fibers (%) —— >99% >99% Lowest Mode Pore 13.5 11.1 7.8 5.2 Diameter (microns) FlowBlocked by the 7% 1%  19%  9% Lowest Mode Pore Diameter (microns) MeanFlow Pore 21.4 29.5 10.1 15.1 Diameter (microns) Bubble Point Pore 67.279 69.1 110.1 Diameter (microns) Low Surface Tension 13 16 32 33 FluidStrikethrough Time (secs) Air Permeability (m/min) 91 72 52 59

Surprisingly, the mean flow pore diameter appears to be more importantthan the bubble point in order to obtain low surface tension fluidstrikethrough times above 12 seconds with untreated (no hydrophobicadditive) nonwoven webs having a basis weight of 15 gsm or less with 3gsm or less fine fibers (i.e., less than 1 micron). Thus, in oneembodiment, a mean flow pore diameter of 15 microns or less,alternatively of 12 microns or less, alternatively of 10 microns or lessis provided. A mean flow pore diameter greater than 1 micron,alternatively greater than 3 microns, and alternatively greater than 5microns, is provided for breathability.

Example 4

In this example, the mechanical bonds of various nonwoven webs areevaluated using the basis weight coefficient of variation (COV) of 900mm² samples. 5 m samples of the same materials are bonded to a 12 gsmtopsheet in a docking station using a hem bond pattern at 3.5 bar and alinear speed of ˜300 m/min. Various samples of web materials BLC1-BLC6are tested. Their various properties are displayed in Table 4.

TABLE 4 Sample No. Material Type BLC1 13 gsm SSMMMS (with 4 gsm M) BLC213 gsm SMMMS (with 1 gsm M) BLC3 13 gsm SMMMS #2 (with 1 gsm M) BLC4 13gsm SSMS (with 1 gsm M) BLC5 15 gsm SNS (1.5 gsm N, sample G) BLC6 15gsm SMS (1 gsm M)

The mechanical bond defects are characterized using the followingcriteria:

“Hole”: an aperture with a size of at least 0.39 mm² in the bond area(hole defect limit). Hole failures are classified as H1, H2, . . . , orH5, with the number reflecting the number of consecutive mechanicalbonds with a hole. Consecutive defects are counted as a single defect,i.e., 5 holes are counted as one H5 defect.

“Skip”: a mechanical bond is missing at least an area of 1.00 mm² (skipdefect limit). Skip failures are classified as S1, S2, . . . , or S5,with the number reflecting the number of consecutive missing mechanicalbonds. Consecutive defects are counted as a single defect, i.e., 5 skipsare counted as one S5 defect.

“Tear”: a tearing of the perimeter such that 1.0 mm or greater of theperimeter of the grommet ring has been torn (tear defect limit). Tearfailures are classified as T1, T2, . . . , or T5, with the numberreflecting the number of consecutive missing mechanical bonds.Consecutive defects are counted as a single defect, i.e., 5 tears arecounted as one T5 defect.

The total number of defects was added up of each kind of defect.

It should be noted that a SSMMMS 13 gsm (sample BLC1) barrier leg cuffshows a significant increase in the number of mechanical bond defects.Extrapolation of a linear fit of BLC1, BLC2, BLC3, and BLC4 leads to anintersection with the horizontal line of BLC6 at a basis weight COV of0.03 (3%). Therefore, a basis weight COV (local basis weight variation)of 0.03 would be needed in order to attain the current levels of defectsfound for the 15 gsm barrier leg cuff when using a 13 gsm barrier legcuff.

FIG. 32 is graphical illustration of the bond defects of samplesBLC1-BLC6 of Table 32 as a function of basis weight COV. The line BLC6represents the average number of defects observed over the range ofbasis weight COV values observed in current 15 gsm barrier leg cuffs.Previous manufacturer trials have shown that the basis weight uniformitymay be increased through increasing the amount of the meltblown basisweight. The results suggests that if 13 gsm barrier leg cuff couldachieve a basis weight COV value of 0.03, it would be theoreticallypossible to attain the current levels of bond defects and bond strengthobserved in the 15 gsm barrier leg cuff.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests,or discloses any such invention. Further, to the extent that any meaningor definition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned tot hat term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. An absorbent article to be worn about the lower torso, the absorbentarticle comprising: a chassis comprising a topsheet, a backsheet, and anabsorbent core disposed between the topsheet and the backsheet; and apair of longitudinal barrier cuffs attached to the chassis, eachlongitudinal barrier cuff formed of a web of material, the web ofmaterial comprising: a first nonwoven component layer comprising fibershaving an average diameter in the range of about 8 microns to about 30microns; and a second nonwoven component layer comprising fibers havinga number-average diameter of less than about 1 micron, a mass-averagediameter of less than about 1.5 microns, and a ratio of the mass-averagediameter to the number-average diameter less than about 2; wherein theweb of material has a local basis weight variation less than about 10%;wherein each of the longitudinal barrier cuffs comprises: a longitudinalzone of attachment where the longitudinal barrier cuff attaches to thechassis; a longitudinal free edge; and a plurality of mechanical bondsdisposed between the longitudinal zone of attachment and the free edge,wherein the plurality of mechanical bonds attach one of: a first portionof the web of material to a second portion of the web of material; andthe web of material to a portion of the absorbent article.
 2. Theabsorbent article of claim 1, wherein each of the pair of longitudinalbarrier cuffs comprises an elastic material, and wherein the elasticmaterial is disposed at least partially intermediate the plurality ofmechanical bonds and the longitudinal free edge.
 3. The absorbentarticle of claim 1, wherein the second nonwoven component layercomprises fibers having a number-average diameter of less than about 1micron, a mass-average diameter of less than about 1 micron, and a ratioof the mass-average diameter to the number-average diameter less thanabout 1.5
 4. The absorbent article of claim 1, wherein the web ofmaterial has a local basis weight variation less than about 7%.
 5. Theabsorbent article of claim 1, wherein each of the plurality ofmechanical bonds has an area of less than about 4 mm².
 6. The absorbentarticle of claim 1, wherein each of the plurality of mechanical bondshas an area less of than about 2 mm².
 7. The absorbent article of claim1, comprising a grommet ring formed around a periphery of each of theplurality of mechanical bonds.
 8. The absorbent article of claim 1,wherein the web of material comprises a third nonwoven component layercomprising fibers having an average diameter in the range of about 8microns to about 30 microns, and wherein the second nonwoven componentlayer is disposed intermediate the first nonwoven component layer andthe third nonwoven component layer.
 9. The absorbent article of claim 1,wherein the web of material comprises: a third nonwoven component layercomprising fibers having an average diameter in the range of about 8microns to about 30 microns; and a fourth nonwoven component layercomprising fibers having an average diameter in the range of about 1micron to about 8 microns; wherein the second and fourth nonwovencomponent layers are disposed intermediate the first nonwoven componentlayer and the third nonwoven component layer.
 10. The absorbent articleof claim 1, wherein the web of material has an air permeability of atleast about 20 m³/m²/min.
 11. The absorbent article of claim 14 whereinthe low surface tension fluid strikethrough time of the web of materialis at least about 19 seconds.
 12. The absorbent article of claim 1,wherein the total basis weight of the web of material is less than about15 gsm, wherein the web of material does not comprise a film, andwherein the web of material has an air permeability of at least about 40m³/m²/min.
 13. An absorbent article to be worn about the lower torso,the absorbent article comprising: a chassis comprising a topsheet, abacksheet, and an absorbent core disposed between the topsheet and thebacksheet; and a pair of longitudinal barrier cuffs attached to thechassis, each longitudinal barrier cuff comprised of a first layer and asecond layer, wherein the a first layer and a second layers have acombined basis weight of less than about 30 gsm, and wherein the firstand second layers are each a web of material comprising: a firstnonwoven component layer comprising fibers having an average diameter inthe range of about 8 microns to about 30 microns; and a second nonwovencomponent layer comprising fibers having a number-average diameter ofless than about 1 micron, a mass-average diameter of less than about 1.5microns, and a ratio of the mass-average diameter to the number-averagediameter less than about 2; wherein at least one of the longitudinalbarrier cuffs comprises: a longitudinal zone of attachment where thelongitudinal barrier cuff attaches to the chassis; a longitudinal freeedge; and a plurality of mechanical bonds, wherein the plurality ofmechanical bonds attach the first and second layers, and wherein theplurality of mechanical bonds have a defect occurrence rate of less thanabout 0.9%.
 14. The absorbent article of claim 13, wherein the pluralityof mechanical bonds are disposed along the longitudinal zone ofattachment and have a defect occurrence rate of less than about 0.54%,and wherein the first layer and a second layers have a combined basisweight of less than about 25 gsm.
 15. The absorbent article of claim 13,wherein the plurality of mechanical bonds attach at least one of thefirst and second layers to a portion of the absorbent article.
 16. Theabsorbent article of claim 13, wherein the web of material has: a localbasis weight variation less than about 10%; an air permeability at leastabout 20 m³/m²/min; and a low surface tension fluid strikethrough timeof at least about 19 seconds.
 17. An absorbent article to be worn aboutthe lower torso, the absorbent article comprising: a chassis comprisinga topsheet, a backsheet, and an absorbent core disposed between thetopsheet and the backsheet; a pair of longitudinal barrier cuffsattached to the chassis, each longitudinal barrier cuff formed of a webof material, the web of material comprising: a first nonwoven componentlayer comprising fibers having an average diameter in the range of about8 microns to about 30 microns; and a second nonwoven component layercomprising fibers having a number-average diameter of less than about 1micron, a mass-average diameter of less than about 1.5 microns, and aratio of the mass-average diameter to the number-average diameter lessthan about 2; wherein the web of material has a local basis weightvariation less than about 10%; and wherein at least one of thelongitudinal barrier cuffs comprises: a zone of attachment where thebarrier cuff attaches to the chassis; a longitudinal free edge; and aplurality of mechanical bonds disposed between the zone of attachmentand the free edge, wherein the plurality of mechanical bonds attach oneof a first portion of the web material to a second portion of the web ofmaterial and the web of material to a portion of the absorbent articleto form a laminate, wherein the laminate of the first portion of the webof material and the second portion of the web of material has a totalbasis weight less than about 25 gsm, and wherein at least most of theplurality of mechanical bonds have a peel strength that is greater thanabout 50% of the tensile strength of the bonded material.
 18. Theabsorbent article of claim 17, wherein each of the plurality ofmechanical bonds has an area less than about 2 mm².
 19. The absorbentarticle of claim 17, wherein each of the plurality of mechanical bondshas an area less than about 4 mm².
 20. The absorbent article of claim17, wherein the web of material has: a local basis weight variation lessthan about 10%; an air permeability of at least about 20 m³/m²/min; anda low surface tension fluid strikethrough time of at least about 19seconds.